Two shortlists fall out of this category, and they barely overlap. One holds the tools you can put a real number against today. The other holds the tools your security reviewer will clear without a six-week detour. Choosing between those two lists is your actual job here, and nobody on either vendor's website will help you do it.

So here's the short version. Gong leads this ranking on depth and on compliance. It holds ISO/IEC 42001:2023, the international standard for AI management systems, and states your data is never used to train generative models. It won't give you a price.

Now the uncomfortable part. A published price tells you nothing about the public record behind it. Lusha publishes a $49.90 plan and rates 1.2/5 across 769 reviews. The lowest published paid price in the field, Unify at $20 a seat, carries exactly one public review. Some of those complaints come from buyers, about billing and stale records. Many come from the people whose mobile numbers ended up in the database you're about to buy. And 11 of these 21 won't put a paid price in front of you.

The whole field on one screen

Those 11 are in the table below with everyone else. Read it down two columns and the shape of your problem shows itself: the longest certification lists mostly sit next to a quote-only price, though UserGems, Amplemarket, Common Room, LeadIQ, Lusha and Apollo all publish both.

Tool	Layer	Published price floor	Free tier	Certifications	Independent rating
1. Gong	Revenue intel	Quote only	No	SOC 2 Type 2, ISO 27001, ISO 42001, ISO 27017/27018, PCI DSS, EU-U.S. DPF	8 Trustpilot reviews; Gong cites 4.5/5 from 6,200+ G2 reviews
2. 6sense	Revenue intel	Quote only	No	SOC 2 Type 2, ISO 27001, ISO 42001, GDPR/CCPA	Capterra 4.6/5, 30 reviews
3. Clari	Revenue intel	Quote only	No	SOC 2 Type II, ISO 27001, ISO 27701, CSA, GDPR	G2 4.6/5, 5,619 reviews
4. UserGems	Data	$40,000/yr plus $3,000 implementation	No	SOC 2	-
5. LinkedIn Sales Navigator	Data	$119.99/month (Core)	No, trial only	-	-
6. Amplemarket	Data	$600/month (Startup, annual)	No	SOC 2 Type II	G2 4.6/5, 664 reviews
7. Backstory	Revenue intel	Quote only	No	SOC 2 Type II, ISO 27001, GDPR/CCPA	Backstory cites 4.5/5 from 630+ reviews
8. Common Room	Data	$2,500/month, 5 seats	No	SOC 2 Type II, GDPR/CCPA	-
9. Apollo.io	Data	Free Starter plan	Yes	SOC 2, ISO/IEC 27001, GDPR	Trustpilot 3.1/5, 1,281 reviews
10. Clay	Data	$54/month (annual Launch)	Yes	-	Trustpilot 2.3/5, 16 reviews
11. Outreach	Revenue intel	Quote only	No	SOC 2 Type II, ISO 27001, ISO 27701, ISO 42001, HIPAA, CSA STAR	-
12. Warmly	Data	$10,000/year	No	GDPR compliant	Trustpilot 4.3/5, 7 reviews
13. LeadIQ	Data	$200/month (Pro)	Yes	SOC 2 Type II, GDPR	Trustpilot 2.3/5, 6 reviews
14. Lusha	Data	$49.90/month (Starter)	Yes	SOC 2 Type II, ISO 27001, ISO 27701, GDPR, CCPA	Trustpilot 1.2/5, 769 reviews
15. Seamless.AI	Data	Free plan; paid tiers quote only	Yes	-	-
16. Salesloft	Revenue intel	Quote only	No	-	-
17. Nooks	Data	Quote only	No	-	G2 4.8/5, 1,697 reviews
18. Demandbase	Revenue intel	Quote only	No	ISO/IEC 27001, SOC 2	-
19. Cognism	Data	Quote only	No	-	Trustpilot 2.9/5, 388 reviews
20. Unify	Data	$20/seat/month (Base)	Yes	-	1 Trustpilot review
21. ZoomInfo	Data	-	No	-	Trustpilot 1.7/5, 329 reviews

A dash is not a pass. Where the certification column is blank, treat it as a question you put in writing before your demo. Ask for the SOC 2 report and for any ISO certificates by number. How long that request takes to come back will tell you something the badge on the website doesn't.

The rating column works differently. Seven sit blank there: UserGems, LinkedIn Sales Navigator, Common Room, Salesloft, Demandbase, Outreach and Seamless.AI. None of that is a verdict. Ask for three references at your size, and go look at the review sites yourself before you rule any of them out.

Are you buying one thing here, or two?

Two, and they get shopped as if they were one. The Layer column above splits them, and keeping them apart in your head is most of the work.

Revenue intelligence leans on data you already own, your calls and your emails, though 6sense and Demandbase pull in third-party signals too. All seven are quote-only, the heaviest certification lists in the table belong to that group, and the risk you underwrite is rollout risk.

The data layer runs the other way. Its records can describe people who never agreed to be in your database, and reviewers say exactly that about Lusha, ZoomInfo, Cognism and LeadIQ. Prices are far more transparent here, and what you underwrite instead is compliance exposure.

So don't compare a $49.90 subscription against a quote-only forecasting platform as though they were substitutes. They land on different budget lines, and different people sign off on them.

Four places to start

Different budget lines mean different starting points. So which constraint binds hardest at your company? Answer that and the table narrows to four picks. Two of the four are combinations rather than single tools.

Security review is the hard gate: Gong plus Common Room. Gong holds ISO 42001 and states your data never trains its models, though you won't get a figure before the call. Common Room runs $2,500/month for five seats and publishes its posture in detail: SOC 2 Type II, General Data Protection Regulation and California Consumer Privacy Act compliance, single sign-on with automated provisioning, third-party penetration testing, a published data processing addendum and a 99.9% uptime commitment.

The budget number has to come first: Unify plus Clay, with Apollo underneath. Unify starts at $20/seat/month, Clay at $54/month billed annually, and Apollo's Starter plan costs nothing. The trade is documentation. Put the SOC 2 request in your first email to all three.

Forecast accuracy is the real problem: Clari, on its own. It carries 4.6/5 across 5,619 G2 reviews, the largest independently reported base here. Buyers report a 2-month implementation and roughly 12 months to return on investment. Budget a full year before it pays anything back.

A certification list to match Gong's: Outreach. SOC 2 Type II, ISO 27001, ISO 27701, ISO 42001, HIPAA (the United States health information privacy rule) and CSA STAR from the Cloud Security Alliance. If your reviewer works through a checklist, that's the shortest meeting you'll have all quarter.

What you'll actually pay

That meeting is the easy one. Three of the four picks above won't show you a number until you're on a call, so start with the nine that will. Is that the nine you want? No. But it's the only ground truth you get before a sales call, so work outward from here.

Unify: Free for up to 3 seats. Base $20/seat/month for 800 credits, Pro $60/seat/month for 2,400 credits with a 14-day trial, Business custom.
Lusha: Free at 40 credits/month, Starter $49.90/month for 400 credits, Professional $69.90/month for 600, Premium $399.90/month for 3,400. Emails cost you 1 credit, phone numbers cost 10.
Clay: Free at 500 actions/month. Launch $167/month or $54/month billed annually, Growth $446/month or $185/month annually, Enterprise custom.
LinkedIn Sales Navigator: Core $119.99/month, Advanced $159.99/month, Advanced Plus custom.
LeadIQ: Free at 1 user and 50 credits, Pro $200/month for up to 5 users, Enterprise custom.
Amplemarket: Startup $600/month on an annual term for 2 users. Growth and Elite are both custom.
Common Room: Essential $2,500/month billed annually with a 5-seat minimum. Advanced and Enterprise are custom.
Warmly: $10,000/year for web de-anonymization, $20,000/year for Inbound Chat, $30,000/year for the Autopilot tier, which Warmly badges as its most popular.
UserGems: Core $3,333/month ($40,000/year), Advanced $6,250/month ($75,000/year), Elite $12,500/month ($150,000/year). Every tier adds an implementation fee running from $3,000 to $10,000.

The other eleven give you no paid number to work with. That's Gong, 6sense, Clari, Backstory, Outreach, Salesloft, Demandbase, Nooks, Cognism, ZoomInfo, and Seamless.AI above its free plan. Apollo.io sits in between, with a free Starter plan and an Unlimited plan bound by a fair use policy of 10,000 credits a month for non-paying accounts.

Rule of thumb: for the quote-only platforms, budget against the nearest published comparable and expect a platform fee on top of your seats. Gong states licenses are priced per user plus a platform fee. Demandbase describes the same shape. The catch is that none of the seven revenue intelligence tools publishes a figure, and the only published comparables in the table sit in the data layer: UserGems Core at $40,000/yr plus a $3,000 to $10,000 implementation fee, Warmly's Autopilot tier at $30,000/yr, and Common Room Essential at $2,500/month, which is $30,000/yr for five seats. Those are not substitutes for a forecasting platform, so treat them as an opening frame rather than an estimate: take a five-figure annual number to finance, shaped as a platform fee plus seats, and expect the quote to correct you. Anchor higher for Clari, which G2 buyers put in the top price tier.

The complaints your legal team should read first

Price is the easy argument. Review scores are harder, because the scores here are not all measuring the same thing. Some of the one-star reviews aren't written by customers at all. They're written by people who got a call from someone using a tool like the one you're buying. Buyers file their own complaints too, about stale records, surprise credits and contracts that are hard to leave.

Theme	Vendors	Evidence
Personal data shared or sold without consent	Lusha, ZoomInfo	Trustpilot 1.2/5 across 769 reviews, 56% of them one star; Trustpilot 1.7/5 across 329 reviews
Opt-out and deletion requests that fail	Lusha, ZoomInfo, LeadIQ	LeadIQ Trustpilot 2.3/5 across 6 reviews; removal requests reported as not working at Lusha and ignored at ZoomInfo
Persistent calls to personal numbers after opt-out	Cognism	Trustpilot 2.9/5 across 388 reviews
Vendor's own compliance claim disputed by name	Cognism, LeadIQ	Cognism markets GDPR-compliant, phone-verified data and reviewers call it not GDPR compliant; LeadIQ states SOC 2 Type II and GDPR compliance and reviewers call the opt-out process dodgy

Why should you care about complaints aimed at the vendor? Because once those records land in your instance, your company is the one processing them. The GDPR doesn't treat your purchase receipt as a defense. So whatever the certification page says, ask the narrower question: when a person emails you asking to be deleted, what happens, and how fast?

That exposure sits almost entirely in the data layer, which is also where the published prices are. The ranking below runs 1 to 21, weighing capability, feature depth, ease of use, integrations, pricing transparency, reliability and trust together, which is why a cheap and easy tool can still finish near the bottom when the trust column is thin.

The ranking

1. Gong

Gong takes the top spot because its compliance page is as substantial as its feature page. That's rarer here than it should be.

The list your reviewer gets: SOC 2 Type 2, ISO/IEC 27001:2022, ISO/IEC 42001:2023, ISO/IEC 27017 and 27018, PCI DSS for payment card data, and EU-U.S. Data Privacy Framework certification.

Gong states your data is never used to train generative models, and its security page claims over 99.5% uptime. Behind that sits a full suite: Gong Engage for engagement, Gong Forecast for pipeline, Gong Enable for coaching, plus Gong Agents, the Gong Revenue Graph and an AI Briefer.

Gong reports 5,000+ customers including Fortune 10 names, so your procurement team will find peers to call. Case studies cite a 64% productivity increase at Anthropic, and 6,700 hours saved with a 32% response-rate lift at Uber for Business.

Your reps may still grumble. Trustpilot reviewers describe an interface that's difficult to navigate and slow to load, with excessive clicks to reach basic information. They also report inconsistent post-sale support and aggressive sales tactics.

The pricing page names no tiers and no figures. It sorts you by team size, from 1-50 up to 10,000+, then hands you a form. Licenses are priced per user plus a platform fee, and there's no free tier or trial.

Layer: Revenue intelligence
Price floor: Quote only
Certifications: SOC 2 Type 2, ISO 27001:2022, ISO 42001:2023, ISO 27017/27018, PCI DSS, EU-U.S. DPF
Independent rating: 8 Trustpilot reviews; Gong cites 4.5/5 from 6,200+ G2 reviews

So is it worth committing without a price? For a 500-seat rollout, probably.

2. 6sense

Gong's pitch is depth. 6sense's is the intent corpus it calls the Signalverse, thirteen years of proprietary data by its own account. It feeds predictive buying-stage models with per-customer explainability, wrapped in a conversational assistant called RevvyAI, AI email agents and omnichannel workflow automation.

Capterra reviewers give it 4.6/5 across 30 reviews, and they consistently praise the intent-data accuracy and the lead scoring. That's the part you're buying. Forrester named it a Leader in the Wave for Revenue Marketing Platforms for B2B, Q1 2026.

Governance is strong too. It's one of only three tools here holding ISO 42001, on top of SOC 2 Type 2 and ISO 27001, and 6sense documents annual CREST-accredited penetration testing plus a HackerOne disclosure program.

Then your team has to use it every day. Those same Capterra reviewers repeatedly flag the interface as unintuitive and clunky, one calling it the worst they have seen.

Cost draws complaints too, particularly Salesforce license scaling as your sales team grows, and international contact coverage is described as limited. All three tiers route you to Book Your Demo, whatever combination of Predictive AI and Data Credits they carry.

Layer: Revenue intelligence
Price floor: Quote only
Certifications: SOC 2 Type 2, ISO 27001, ISO 42001, GDPR/CCPA
Independent rating: Capterra 4.6/5, 30 reviews

Shortlist it if intent data is the thing you're genuinely short of. The interface will cost you adoption either way, so budget for training.

3. Clari

Adoption is one risk. A missed number is another, and Clari is the pick when you can't afford a surprise. It carries the largest independently reported review base in this ranking, 4.6/5 across 5,619 G2 reviews, and Clari says 1,500+ customers manage a combined $5 trillion in revenue on it.

Security covers SOC 2 Type II, ISO/IEC 27001 and ISO/IEC 27701, with a public status page your reviewer can check and a vulnerability disclosure program. Seven modules run over a unified revenue database: Capture, Inspect, Align, Forecast, Guide, Copilot and Groove.

Gartner names Clari a Magic Quadrant Leader for Revenue Action Orchestration, and a Forrester study cited by Clari documents 398% return on investment.

Dependable doesn't mean quick. G2 buyers report an average 2-month implementation and roughly 12 months before that return shows up. They also place Clari in G2's top price tier, so expect your quote to reflect that.

Every deal here is quoted individually, and your rollout will cost real money on top of the license. Budget for both.

Layer: Revenue intelligence
Price floor: Quote only
Certifications: SOC 2 Type II, ISO 27001, ISO 27701, CSA, GDPR
Independent rating: G2 4.6/5, 5,619 reviews

If the forecast number is what your board argues about, demo this one first.

4. UserGems

Start with the number, because UserGems does, and because it'll decide this for you.

Core: $3,333/month ($40,000/year), 4,000,000 credits, 2-4K account coverage
Advanced: $6,250/month ($75,000/year), 10,000,000 credits, 4-10K accounts
Elite: $12,500/month ($150,000/year), 25,000,000 credits, 10K+ accounts
Implementation: $3,000 to $10,000, charged on every tier

There's no free plan and no trial for you to test first. What you buy is Gem-E, a scoring model UserGems describes as reading 600+ signals and learning from your closed-won patterns.

UserGems lists 30+ native buying signals around it, including job changes, contact-level intent and merger activity, plus a Research Agent for signals you define yourself.

Integrations are broad, and they likely cover your stack: Salesforce, HubSpot, Microsoft Dynamics, Outreach, Salesloft, Gong Engage, Marketo, and the LinkedIn, Meta and Google ad platforms.

Security documents SOC 2 with continuous monitoring, AES-256 encryption at rest, single sign-on, two-factor authentication and annual third-party penetration testing.

The customer evidence is all self-published, so weigh it against references you find yourself. Mimecast reports $20M in pipeline over two years, Docebo 54 enterprise opportunities in a quarter, CaptivateIQ $1.3M in ten weeks.

Layer: Signal and contact data
Price floor: $40,000/year plus $3,000 implementation
Certifications: SOC 2
Independent rating: -

Get finance to sign off on the $40,000 before you book the demo.

5. LinkedIn Sales Navigator

Not every entry needs finance in the room. Your team already knows how to use this one, and that's worth more than most feature comparisons admit. Core runs $119.99/month ($1,079.88/year), Advanced $159.99/month ($1,799.88/year), and Advanced Plus is custom.

LinkedIn puts the database at 1B+ members, with 50+ search filters, real-time alerts, TeamLink, Relationship Map, Smart Links, and one-click AI summaries through Account IQ and Lead IQ.

LinkedIn reports 1.5M+ sellers on the platform, and some of them already sit on your team. It cites a Forrester study from October 2023 finding the product pays for itself in under six months.

Watch the tier boundaries, because that's where your real cost hides. Customer relationship management (CRM) integrations with Salesforce, HubSpot, Microsoft Dynamics 365 and Oracle Sales are Advanced Plus only. So is buyer intent.

Message Assist, the AI personalization feature, is still labeled public beta. There's no permanent free tier either, only a trial that needs a credit card and excludes anyone who has held a paid LinkedIn subscription in the past 365 days.

Layer: Signal and contact data
Price floor: $119.99/month
Certifications: -
Independent rating: -

Buy the seats your reps will use anyway. Price Advanced Plus separately, the day buyer intent becomes the argument.

6. Amplemarket

That one you buy by the seat. Amplemarket bundles the contact data and the sending into one subscription, and it names every piece. Duo Copilot builds multichannel sequences off signals like job changes and competitor mentions.

Duo Copywriter drafts the email, Duo Inbox drafts the reply, and Duo Voice clones one of your reps' voices for notes. G2 gives it 4.6/5 across 664 reviews with an 8-month reported payback, and lists a 1-month average implementation. That's quick for something this broad.

It's SOC 2 Type II certified, with encryption in transit and at rest through Google Cloud key management, code scanning and regular penetration testing.

Amplemarket lists 28+ native connectors, including Salesforce, HubSpot, Pipedrive, the CloudTalk, Orum and Nooks dialers, WhatsApp, and Zapier for another 8,000+ apps.

So where's the catch? In the shape of the pricing. Startup is $600/month on an annual term and includes just 2 users, with 27,000 email credits per user per year.

Growth and Elite are both custom, and G2 reviewers already flag the platform as expensive against its peers. You get a trial, but no permanent free plan.

Layer: Signal and contact data
Price floor: $600/month
Certifications: SOC 2 Type II
Independent rating: G2 4.6/5, 664 reviews

Two users at $600/month is the real entry cost, and everything above it is custom. Your headcount decides this one, not the feature list.

7. Backstory (formerly People.ai)

Most of these entries start with the feature list. Backstory starts with a data-handling promise, and on the point that matters most it matches Gong's. Your data never trains its models. Personally identifiable information is stripped before anything reaches a model provider.

Access is just-in-time with no standing privileges, and you can switch the AI features off at the tenant level entirely. That sits on SOC 2 Type II and ISO 27001 audited annually, GDPR and CCPA compliance, and a 99.5% uptime service level agreement.

The product captures your emails, meetings, calls and chat automatically, so your reps stop logging activity by hand. It then scores deal risk, pipeline health, forecast accuracy and stakeholder coverage off your own activity record.

It connects to Salesforce, Microsoft Dynamics and Oracle, supports multiple CRMs at once, and delivers answers inside Claude, ChatGPT and Gemini through a Model Context Protocol server.

Pricing is a consumption model Backstory calls True Forward, billed per connected rep and per answer consumed. You have to call to find out what that means for you.

And the 4.5/5 from 630+ reviews on its homepage is the vendor's own figure.

Layer: Revenue intelligence
Price floor: Quote only
Certifications: SOC 2 Type II, ISO 27001, GDPR/CCPA
Independent rating: Backstory cites 4.5/5 from 630+ reviews

Worth a call if your activity data is already flowing into the CRM. If it isn't, fix that first.

8. Common Room

Backstory reads the data you already own. Common Room looks outside it, and that's the pick when your buyers live in places a contact database can't see. It says it pulls 50+ signal channels spanning CRM, community, code and social sources, including GitHub, LinkedIn, X, Reddit, Stack Overflow and Discord.

Common Room puts the directory it joins them to at 400M+ contacts, reached through what it calls Context360. Its AI layer, RoomieAI, ships as named agents: Spark Brief, Ask CR Anything, DataAgent and Actions.

Integration depth is genuinely wide:

CRM and marketing: Salesforce, HubSpot, Marketo
Sales engagement: Gong, Outreach, Apollo, Salesloft
Warehouses: Snowflake, BigQuery, Redshift
Build your own: an application programming interface (API), a Model Context Protocol server and Zapier

Security covers SOC 2 Type II, GDPR and CCPA, single sign-on with automated provisioning, third-party penetration testing, a published data processing addendum and a 99.9% uptime commitment.

Entry costs you $2,500/month billed annually, with a 5-seat minimum, 100k contacts and 5k research credits. Onboarding comes through a shared customer success manager. Advanced (15 seats, 250k contacts) and Enterprise (30 seats, 750k contacts) are both custom.

Its customer page names Anthropic, Notion, Superhuman and Asana, so you'll find peers to call. Semgrep reports 74% more pipeline in a quarter, and Temporal's VP of Sales says over half the company's meetings now come from it.

Layer: Signal and contact data
Price floor: $2,500/month, 5 seats
Certifications: SOC 2 Type II, GDPR/CCPA
Independent rating: -

A defensible contact-layer pick when security leads the review, because the documentation is there to read on day one. Bring $30,000 a year to the table.

9. Apollo.io

$30,000 a year is a lot to commit before you've tested anything. Apollo asks for nothing up front, and you can see the appeal. There's a free Starter plan. Apollo puts the database at 240M+ verified contacts and 30M+ company profiles.

One subscription spans prospecting, enrichment, multichannel outbound, inbound lead routing, and deal execution features like meeting prep, call summaries and conversation intelligence. Apollo reports 40,000 paying customers and a million sales professionals.

It integrates natively with your CRM if that's Salesforce or HubSpot, plus Chili Piper, Adobe Marketo, and the AI tools Claude, ChatGPT and Perplexity. Its homepage states GDPR, SOC 2 and ISO/IEC 27001 compliance.

The user record is more mixed than the marketing, so read it before your trial ends. Trustpilot shows 3.1/5 from 1,281 reviews, against the 4.7/5 from 9,690 reviews Apollo cites on its own about page.

Reviewers describe the interface as cluttered and frustrating, with a steep learning curve. They call support slow and hard to reach. They raise contact-accuracy problems, and credit consumption beyond what the subscription seemed to cover.

Layer: Signal and contact data
Price floor: Free Starter plan
Certifications: SOC 2, ISO/IEC 27001, GDPR
Independent rating: Trustpilot 3.1/5, 1,281 reviews

Start on the free tier and give it two weeks. The credit line on your first invoice will tell you more than the demo did.

10. Clay

Apollo's free tier gets you in the door. Clay's does the same, and its $0 plan is an allowance rather than a countdown. You get 500 actions and 100 data credits every month, indefinitely.

That's enough to run waterfall enrichment across what Clay counts as a 200+ provider marketplace, point a Claygent research agent at a list, and find out whether the spreadsheet-style interface fits how your team thinks. All before finance is involved.

Paid tiers publish real numbers too. Launch is $167/month or $54/month billed annually with a 15,000-action minimum. Growth is $446/month or $185/month annually at 40,000 actions. Enterprise is custom above 200,000.

Connectors cover the whole chain:

CRM: Salesforce, HubSpot, Pipedrive, Attio, Dynamics 365
Sequencers: Outreach, Salesloft, Instantly, Smartlead
Warehouses: Snowflake, BigQuery, Databricks

Clay reports 500,000+ go-to-market teams and a $5 billion valuation, with Intercom citing 140% outbound pipeline growth and Vanta 80%+ enrichment coverage.

The complaints cluster around money and help. Trustpilot rates it 2.3/5 across 16 reviews, dominated by surprise credit consumption and a recurring subscription charge arriving with no advance reminder.

Support is described as unresponsive, including one reviewer told to ask a large language model for help debugging. Others describe simple lookups turning into endless research.

Layer: Signal and contact data
Price floor: Free, then $54/month annually
Certifications: -
Independent rating: Trustpilot 2.3/5, 16 reviews

So is the free tier a trap? No. The invoice is. Cap the credits on day one.

11. Outreach

Clay's certification row is blank. Outreach has the compliance paperwork most of this list wishes it had. SOC 2 Type II, ISO 27001, ISO 27701, ISO 42001, HIPAA and CSA STAR, plus a claim to being the first revenue platform certified in responsible AI.

It's one of three tools here carrying ISO 42001, the certificate your AI governance reviewer will ask for by name.

The platform is agent-shaped throughout: an Omni Agent, Research Agent, Deal Agent, Revenue Agent and Personalization Agent, alongside AI Coach Cards, sentiment analysis, AI forecasting, a scenario planner and territory management.

By Outreach's own count it processes over 2 million opportunities a month for customers including Zoom, Snowflake, ServiceNow, Databricks, Siemens and Avis, across 90+ supported integrations.

Here's where the credit question bites into your budget. All four Amplify tiers are custom-quoted, and what actually separates them is consumption:

Essentials: 10,000 AI credits a month, 250,000 API calls
Core: 25,000 AI credits, 250,000 API calls
Plus: 50,000 AI credits, 500,000 API calls
Pro: 100,000 AI credits, 1,000,000 API calls

So the tier you get quoted is a consumption bet. Bring your own usage estimate to that conversation. There's no free tier and no trial to soften your first commitment.

Layer: Revenue intelligence
Price floor: Quote only
Certifications: SOC 2 Type II, ISO 27001, ISO 27701, ISO 42001, HIPAA, CSA STAR
Independent rating: -

The certification list is the whole reason to look at this one. Whatever usage number you bring to the call is what the quote gets built around.

12. Warmly

Outreach wants your whole revenue cycle. Warmly answers one narrow question instead. Who is on your website right now, and which human is it? It markets identification at the person level rather than the company level.

Off that identity it runs AI chat, personalized landing pages, popups, lead routing and meeting booking on your site, with a TAM Agent scoring your total addressable market and coordinated email and LinkedIn campaigns on the outbound side.

One Context Graph data layer sits under all of it, which Warmly says connects to 40+ tools in your stack. Warmly doesn't publish the full connector list, so ask for it in writing before you count on any specific integration. The seven Trustpilot reviewers rate it 4.3/5 and single out the AI-driven lead qualification, plus a smooth HubSpot setup with responsive support.

Pricing is published, and steep:

AI Web-Deanonymization: $10,000/year, from 10K credits a month
Inbound Chat: $20,000/year, one AI Studio agent
AI Inbound Autopilot: $30,000/year, unlimited agents, badged by Warmly as its most popular tier
GTM Signals package: $10,000/year for extra intent coverage

No free plan, no trial. Seven reviews is a thin base for your five-figure commitment, so lean hard on references here.

Layer: Signal and contact data
Price floor: $10,000/year
Certifications: GDPR compliant
Independent rating: Trustpilot 4.3/5, 7 reviews

This is a narrow tool at a wide price. It earns the $10,000 only where inbound traffic is already the strongest channel.

13. LeadIQ

Warmly wants five figures up front. LeadIQ starts at zero, and if your sales development team already lives inside Salesforce or HubSpot, it sits neatly in the workflow. The integration list covers the tools around it:

CRM: Salesforce, HubSpot
Sales engagement: Outreach, Salesloft, Gong, Groove by Clari
Dialers: Nooks, Orum
Workflow: Zapier, Workato, Clay, Chili Piper

Champion Tracking watches for job changes among people who already bought from you, so a buyer who already knows the product turns up as a new account to work. AI Account Prospecting and the Lando conversational agent handle the research for your reps.

You get a real $0 tier at 1 user and 50 credits, Pro at $200/month for up to 5 users with 25% off annually, and a custom Enterprise plan.

LeadIQ's case studies report WalkMe saving 1,000 hours a quarter with 19% more discovery calls, Optimizely $2M in pipeline in a year, and Clari 600 hours a quarter.

The public record is small, and what there is of it is bad. Trustpilot sits at 2.3/5 across 6 reviews. Reviewers complain that data was collected and used without clear consent, particularly from EU contacts, and that unsolicited outreach followed.

One reports a signup flow that failed with support unable to fix it. LeadIQ states SOC 2 Type II and GDPR compliance, which those reviewers dispute by name.

Layer: Signal and contact data
Price floor: Free, then $200/month
Certifications: SOC 2 Type II, GDPR
Independent rating: Trustpilot 2.3/5, 6 reviews

Six reviews prove nothing on their own. They do tell you exactly which questions to put in writing.

14. Lusha

Six reviews leave room for doubt. Lusha has 769, and few tools here split the buyer experience from the data-subject experience so sharply.

The product story is strong. Lusha claims 290M+ verified contacts and 28M+ companies with 77 verified fields, at 98% accuracy on email and 86% on phone.

An intelligence layer recommends accounts and contacts to your reps, and buying signals cover funding events, hiring changes and leadership transitions. Pricing is unusually transparent for this category:

Free: 40 credits a month
Starter: $49.90/month, 400 credits
Professional: $69.90/month, 600 credits
Premium: $399.90/month, 3,400 credits

Credits roll over, and you pay 1 credit per email and 10 per phone number. Integrations reach into your stack: Salesforce, HubSpot, Monday, Zoho, Clay, Make, n8n, Zapier, a direct API, a Model Context Protocol connector, and Claude, ChatGPT, Gemini and Perplexity.

Now the other column. Trustpilot shows 1.2/5 from 769 reviews, 56% of them one star. That's the lowest of the numeric ratings in this ranking.

The dominant complaint is personal contact data shared or sold without consent, producing unsolicited calls, and reviewers report that opt-out and removal requests don't work. Others describe unresponsive support and difficulty getting refunds after unexpected auto-renewals.

Lusha states GDPR, CCPA, SOC 2 Type II, ISO 27001 and ISO 27701 compliance, and names Google, Snowflake, Zendesk and Oracle NetSuite among 280,000+ revenue teams. Both columns are on the record.

Layer: Signal and contact data
Price floor: Free, then $49.90/month
Certifications: SOC 2 Type II, ISO 27001, ISO 27701, GDPR, CCPA
Independent rating: Trustpilot 1.2/5, 769 reviews

Take this one to your legal team before you take it to your reps.

15. Seamless.AI

Every database here came from somewhere. Seamless.AI's comes from crawling the web in real time. It claims 1.8B+ verified business emails, 414M+ phone numbers and 100+ live data points per profile.

Around that database sit five named agents: Outbound, Inbound, Ops, Marketing and Customer Success. You also get an Engagement Hub, an AI Assistant, and Model Context Protocol and API automation.

The free plan is genuine. That's $0, 50 credits, 1 user, where one credit covers a phone number and an email, with a knowledge base, email support and a live training webinar.

Seamless.AI publishes a 100% Credit Back Protection guarantee on invalid emails behind that, which is a commitment you can hold it to in writing.

Above the free plan, your numbers stop. Pro is quoted per user against annual credit packages starting at 10,000 credits a year. Enterprise is a custom daily credit allotment across five or more license tiers, with unlimited users.

Layer: Signal and contact data
Price floor: Free; paid tiers quote only
Certifications: -
Independent rating: -

Apollo's free tier covers the same first pass and carries a published SOC 2 and ISO 27001 behind it. That's the comparison worth making while your 50 credits are still unspent.

16. Salesloft

Paperwork was thin there. It's thin here too, and Salesloft's argument is the ecosystem around your stack instead. It publishes 180+ integrations, including native Salesforce, Highspot, 6sense, DocuSign and Drift, and calls that the largest integration ecosystem for revenue teams.

The product spans your funnel: Cadence for automation, Rhythm for prioritization, Conductor AI, AI Email Agents, AI Forecast, Conversation Intelligence, deal management and chat agents.

Scale isn't in question. Salesloft's homepage puts it at 4,000+ customers including IBM, Stripe, Siemens, SAP Concur and 3M, so you can find references at your size.

Its case studies report 3M closing deals 2.5x faster and NFP generating over $1M in revenue on the platform, and its platform page claims sellers who use AI are 3.7x more likely to hit quota.

What does the pricing page give you? A Talk to Sales prompt, and nothing else. Put the pricing model and the audit reports on your first-call agenda together.

Layer: Revenue intelligence
Price floor: Quote only
Certifications: -
Independent rating: -

The integration ecosystem is the strongest thing on this entry. The paperwork is among the thinnest, with nothing in the certification column.

17. Nooks

Salesloft gives you no independent rating. Nooks has the highest one here, 4.8/5 across 1,697 G2 reviews. Is 1,697 a real base to lean on? Yes, and it should give you some confidence.

It's built for outbound teams that live on the phone. If that's your team, the dialer is the reason to look. The AI Dialer is marketed as connecting your reps with 3x more prospects through parallel dialing.

Around it sit AI Sequencing across channels, Signals and Intelligence for research, and AI Coaching with call scoring and roleplay. Nooks recently deepened that last piece by acquiring the AI sales-coaching platform FullyRamped.

Nooks' own site cites over 1,200 customers, among them HubSpot, Deel, Greenhouse, Seismic, Spring Health, Pendo and Drata. Reviewers report doubled email-sourced pipeline and roughly 90% less time spent on prospect research.

Two cautions before it goes on your shortlist. Pricing comes as a custom quote, and there's no trial to test the dialer on your own list first. And some buyers question the overlap between an all-in-one workspace and specialist tools, particularly dedicated intent-signal platforms like UserGems.

Deliverability comes up too, around DMARC and DKIM, the email authentication records that decide whether your mail lands.

Layer: Signal and contact data
Price floor: Quote only
Certifications: -
Independent rating: G2 4.8/5, 1,697 reviews

Strongest fit for a dialing team. Weakest fit for a team that already owns a signal platform.

18. Demandbase

Nooks fits a dialing team. Demandbase fits an account team: it's an account-based play first and a sales intelligence tool second. Its Sales Intelligence product maps buying groups, tracks intent and engagement signals, prioritizes your pipeline by fit and activity, and surfaces next best actions inside the seller's workflow.

All of that sits under a broader platform covering account-based marketing, B2B advertising and account data. The customer roster on its site reads like an enterprise reference list you could actually call: Visa, SAP Concur, IBM, Salesforce, Adobe, DocuSign, Gong and Zoom.

Demandbase states ISO/IEC 27001 and SOC 2 certification. That's a checkable claim, and a meaningful one at this end of the market.

So what's missing? Specifics. Pricing is a form. Demandbase describes it as flexible and structures it as a platform fee plus a flat fee per user.

The Sales Intelligence page also names no CRM or sales-engagement partner, which is an odd gap for a tool that lives inside the seller's workflow.

Layer: Revenue intelligence
Price floor: Quote only
Certifications: ISO/IEC 27001, SOC 2
Independent rating: -

Ask for the connector list before you spend a week on this one.

19. Cognism

Geography decides the next one. If your market is the UK and Europe, Cognism belongs on your evaluation list, because that's where reviewers say its mobile-number accuracy holds up.

The Standard plan covers firmographic and technographic filtering, AI research and CSV enrichment. Pro adds higher-quality mobile data, on-demand verification and intent data. CRM Enrichment and a Data-as-a-Service API tier sit alongside as usage-based options, and both prospecting tiers include 5 seats.

Integrations cover your stack: Salesforce, HubSpot, Pipedrive, Bullhorn, Microsoft Dynamics, Salesloft, Outreach and Zapier. Reviewers consistently praise the interface and browser extension as clean and simple for your reps to navigate.

Cognism reports 4,000+ revenue teams including Asana, Notion, Aircall, AVEVA and Seismic. So why does it sit at 19? Because 388 Trustpilot reviews average 2.9/5.

The recurring themes are unsolicited and persistent calls to personal numbers after opt-out requests, and personal data retained without consent. Reviewers state flatly that the company is not GDPR compliant, which is the exact opposite of what the marketing claims.

Some also report that over half the records they pulled were out of date, which undercuts the core promise you're paying for. Pricing is contact-sales throughout, with no published credit costs and no free tier.

Layer: Signal and contact data
Price floor: Quote only
Certifications: -
Independent rating: Trustpilot 2.9/5, 388 reviews

Buy it for the European mobile numbers and you also inherit 388 reviews' worth of argument about how those numbers were collected.

20. Unify

Cognism won't put a number in front of you. Unify will. Base is $20/seat/month for 800 credits per seat, the lowest published paid price of the 21.

Under it sits a genuine $0 tier for up to 3 seats, and above it Pro at $60/seat/month for 2,400 credits with a 14-day trial. Business is custom.

Unify's pricing page puts the database underneath all of that at 1.1B+ people and 65M+ companies drawn from 40+ data sources. It feeds signal-triggered Plays, AI agents with 50+ native skills, AI email copywriting, job-change and hiring signals, managed mailbox provisioning, and a phone dialer in beta at the top tier.

Unify reports $786M+ in pipeline powered across its customer base, and a $40M Series B per its funding announcement, naming Perplexity, Justworks, Guru and Navattic among them.

Check two things before you commit. Named CRM integrations are HubSpot and Salesforce only, and the sync is read-only below the Business tier. So if you need write-back, you're pricing the custom plan rather than the $20 one.

Website intent signals and managed mailboxes sit behind that same gate. And the public review footprint is a single Trustpilot review, negative, about a pre-sales experience. Too little to conclude anything in either direction.

Layer: Signal and contact data
Price floor: Free, then $20/seat/month
Certifications: -
Independent rating: 1 Trustpilot review

Clay is the other cheap way into this layer, and the two ladders run the same shape: a free tier, two published paid tiers, then a custom quote at the top. The phone call arrives at the same step either way, so choose on how the products work rather than on when the pricing page runs out.

21. ZoomInfo

Unify has one review. ZoomInfo has 329, and it still ranks last, for reasons that have nothing to do with size. It's been public since 2020, with $1.21 billion in FY2024 revenue and 3,508 employees.

Its capability set was assembled through acquisitions including Chorus.ai for conversation intelligence, plus NeverBounce, Datanyze, RainKing and RingLead.

So why last? Because of what the public record says about how the database gets built. ZoomInfo is described as a data broker that collects and sells personal data, both public and private, through data and web scraping.

It faces multiple lawsuits over unauthorized data collection, alongside claims of misleading investor disclosures. Trustpilot shows 1.7/5 across 329 reviews, 69 of them in the last twelve months. So the pattern is live.

Reviewers report personal data sold without consent and deletion requests ignored. Buyers add complaints about outdated contact records and difficulty canceling contracts.

They do credit it with making prospects easy to find and contact, and say support staff resolve issues well once you reach someone. That's the trade you'd be signing.

Layer: Signal and contact data
Price floor: -
Certifications: -
Independent rating: Trustpilot 1.7/5, 329 reviews

Sign here and every deletion request behind those 329 reviews becomes your company's problem rather than the vendor's.

Before you sign: the questions that decide this

Whatever you sign, you inherit its gaps. So take this list into the demo, then into your own legal review. Every item comes from something this category leaves open, and each one is cheaper to settle now than in month four.

What happens when you exceed the credits? Get the overage rate and the renewal terms in writing. Outreach's four tiers differ mainly by AI credits. Clay reviewers report surprise consumption and charges arriving with no reminder. Apollo reviewers cite credit use beyond the subscription, and LeadIQ's Pro credits fragment across sub-tiers from 200 to 6,750 a month.
What is your opt-out and deletion service level? Ask for the process and the clock, in days. Opt-out and deletion failures recur across Lusha, ZoomInfo and LeadIQ, alongside complaints that the data was collected without consent in the first place.
Does customer data train your models? Gong and Backstory both state that it does not. A vendor who can't answer that in one sentence hasn't thought about it, and you'll inherit the consequences.
What is the implementation fee, and who pays for the rollout? UserGems charges $3,000 to $10,000 on every tier. Clari buyers report a 2-month average implementation and roughly 12 months to return on investment. G2 reviewers put Amplemarket at a 1-month implementation and an 8-month payback.
Which tier unlocks CRM write-back and buyer intent? Unify keeps write-back for Business. LinkedIn Sales Navigator keeps CRM integrations and intent for Advanced Plus. Both of those are custom-priced.
Which certifications can you produce today? Ask for the SOC 2 report and the ISO certificates themselves. A badge on a website proves nothing. If AI governance matters to your reviewer, ask specifically about ISO 42001, which Gong, 6sense and Outreach hold.
Can you name three reference customers at my company size, running my CRM? For the seven tools with no rating in the table above, that's the strongest evidence you can get before you sign.

Questions buyers keep asking

Those seven questions go to the vendor. These three come up well before you get anyone on a call.

Which AI sales intelligence tools have a genuinely free plan rather than a trial?

Six of them, and you can start on any of those today. Apollo.io (Starter), Clay (500 actions and 100 data credits a month), LeadIQ (1 user, 50 credits), Lusha (40 credits a month), Seamless.AI (50 credits, 1 user) and Unify (up to 3 seats). LinkedIn Sales Navigator and Amplemarket offer trials instead, and the LinkedIn trial requires a credit card and excludes anyone who held a paid LinkedIn subscription in the past 365 days. Clay's 500 actions and Lusha's 40 credits refill every month, and Unify's free tier runs up to 3 seats on an ongoing basis, so any of those three can carry a real evaluation while you build the workflow you actually intend to run.

Is buying B2B contact data a GDPR risk for my company?

It's a risk you take on yourself, yes. Once those records sit in your systems, you're processing them, and the obligations follow you whatever the vendor's certification page says. Lusha (1.2/5, 769 reviews), ZoomInfo (1.7/5, 329 reviews), Cognism (2.9/5, 388 reviews) and LeadIQ all draw recurring complaints from data subjects about contact data used without consent and opt-out requests that fail. In several cases that contradicts the vendor's own compliance claim, and ZoomInfo also faces lawsuits over unauthorized data collection. None of this makes the purchase impossible. It does mean you should be testing the deletion workflow, not the badge.

Which of these tools will pass an enterprise security review?

Eight of them can't even start one until you ask. For LinkedIn Sales Navigator, Clay, Seamless.AI, Salesloft, Nooks, Cognism, Unify and ZoomInfo, you'll need to request the documentation directly before the review can begin, so send that email the same day you book the demo. A blank in a comparison table is your prompt to ask, never your answer.

Explore AI Sales Intelligence Tools