"Sales intelligence" has become a catch-all category label that covers tools with fundamentally different data models. ZoomInfo and Apollo sell contact databases. 6sense and Bombora sell intent data. LinkedIn Sales Navigator sells network and relationship intelligence. Cognism sells phone-verified contact data for EMEA markets. Each of these occupies a different position in the sales intelligence stack, and the question of which is "best" only makes sense after you've defined which problem you're actually trying to solve.
This comparison covers the six most commonly evaluated sales intelligence tools, what each one is actually optimized for, and the patterns in G2 review data that reveal real-world performance gaps that vendor pages don't mention.
| Tool | G2 Rating | Starting Price | Primary Data Type | Best For |
|---|---|---|---|---|
| ZoomInfo | 4.4 (2,600+) | ~$15K+/year | Contact + company data | Enterprise NA outbound |
| Apollo | 4.7 (9,400+) | $49/user/mo | Contact data + sequencing | SMB all-in-one outbound |
| Cognism | 4.6 (700+) | Quote only | Phone-verified contact data | EMEA SDR outbound |
| 6sense | 4.3 (900+) | ~$60K+/year | Intent + predictive AI | Enterprise ABM prioritization |
| Bombora | 4.4 (200+) | Quote only | Third-party intent data | Layering intent on any stack |
| LinkedIn Sales Navigator | 4.3 (1,900+) | $99.99/user/mo | Network + relationship intel | Social selling, warm intros |
Contact data tools: ZoomInfo, Apollo, Cognism
These three tools occupy the same category — B2B contact and company data — but differ on price, geography, and what they include alongside the database.
ZoomInfo is the market leader for North American enterprise coverage. Its database of over 300 million contacts includes depth of company intelligence that goes beyond what most alternatives provide: organizational hierarchy data, technology stack information, department-level headcount, and intent signals as an add-on. The platform includes a built-in sequencer (Engage) and website visitor identification (WebSights) for teams that want one vendor across multiple use cases.
The limitations are cost and contracts. G2 reviewers cite annual commitments starting around $15,000, auto-renewal friction, and difficulty reducing seats as the most common operational complaints. Data quality for non-US markets is also a recurring theme — for teams selling globally, ZoomInfo's European coverage is materially thinner than its US database.
Apollo has the most reviews of any sales intelligence tool on G2 (9,400+), which is both a signal of market penetration and a large enough data sample to draw reliable conclusions about its weaknesses. Data accuracy complaints appear in hundreds of reviews — specifically outdated job titles, bounced emails, and disconnected phone numbers. The platform's strength is value per dollar: database plus sequencer plus email sending infrastructure starting at $49 per user per month is genuinely hard to beat for small teams running North American outbound.
Apollo's Trustpilot score (2.9/5 across 1,000+ reviews) is notably lower than its G2 score, which typically indicates concentrated complaints around billing and post-purchase experience rather than the product itself. For high-stakes outreach where data accuracy matters, teams often use Apollo as a starting point and layer in verification or supplement with a higher-accuracy source for priority accounts.
Cognism solves a specific problem: EMEA coverage and phone-verified mobile numbers. For teams whose ICP is concentrated in European markets, Cognism's data is more current and more compliant than what ZoomInfo provides for the same accounts. Its Diamond Data product — human-verified mobile numbers for high-priority contacts — is the clearest differentiator in the mobile data space. Connect rates for SDR programs in the UK and DACH region are consistently reported as meaningfully higher than competing databases for the same accounts.
Cognism's limitation is that it doesn't include a sequencer. Teams need to integrate it with an existing CRM and outbound tool, which adds toolchain complexity. For teams that already have Salesforce and Outreach or HubSpot and a sequencer, the integration is straightforward. For teams looking for a single platform, ZoomInfo or Apollo are simpler to operationalize.
Intent data tools: 6sense and Bombora
Intent data tools don't replace contact databases — they layer on top of them. The core value proposition is identifying which accounts are actively researching a purchase before they've engaged with your marketing or sales channels. Both 6sense and Bombora do this, but through different mechanisms and at different price points.
6sense is the full-platform version of intent data. It takes third-party intent signals (from publisher networks, review sites, and search behavior), first-party engagement data (website visits, email engagement), and firmographic data, and produces a predictive model that assigns each account in your TAM a buying stage: awareness, consideration, or decision. The output is a prioritized account list that SDRs and marketers can act on weekly.
The value of that model depends on how well-defined your ICP is and how much historical conversion data 6sense can use to calibrate its predictions. Companies with tightly defined ICPs and 18+ months of CRM data to train the model on see stronger signal quality than companies earlier in their go-to-market journey. The 60 to 90 day configuration period that most 6sense reviewers describe is real — the platform produces reliable signals faster when there's more historical data to learn from.
Bombora takes a simpler approach: it tracks keyword research activity across a network of 5,000+ B2B publisher sites and surfaces companies that are reading content related to your product category at elevated rates compared to their baseline. The output is a topic-level surge score by company, which can be fed directly into CRM, marketing automation, or an ABM platform via integrations.
Bombora is often the more practical starting point for teams that want intent data but can't justify a full 6sense or Demandbase contract. Its data integrates cleanly into existing stacks — you can use Bombora intent signals in Salesforce, HubSpot, or Marketo without buying the full ABM platform — and the investment is lower. The limitation is that Bombora's topic-level signals are less predictive than 6sense's buying stage model; you know a company is reading about "data enrichment," but you don't know if they're in an evaluation cycle or just doing background research.
LinkedIn Sales Navigator: network intelligence, not contact data
LinkedIn Sales Navigator is the most widely used sales intelligence tool by seat count, partly because it's included in many enterprise LinkedIn contracts and partly because every B2B professional has a LinkedIn profile while not every professional appears in third-party contact databases.
Sales Navigator's differentiation is relationship intelligence rather than contact data. It surfaces mutual connections between your team and target accounts, tracks job changes and company news in real time, shows which of your contacts have engaged with a target company recently, and surfaces "TeamLink" introductions — warm paths to contacts through your company's collective LinkedIn network. These signals are uniquely LinkedIn's; no other sales intelligence tool has access to the relationship graph at the same scale.
Sales Navigator doesn't provide direct dials or email addresses. It complements ZoomInfo or Apollo rather than replacing them: use Sales Navigator to identify the right person and understand the context, use a contact database to find their email and phone number. Most enterprise sales stacks include both, and the ROI case for the combination is well-established among teams with structured social selling programs.
How to stack these tools
The most common configuration for a well-resourced growth-stage company (Series B+, 10–30 reps) is: Apollo or ZoomInfo as the primary contact database, LinkedIn Sales Navigator for relationship and network intelligence on priority accounts, and Bombora or 6sense for intent data when the team is ready to act on buying signals systematically. That's three tools at potentially meaningful cost, but each one is performing a different function that the others don't cover.
Smaller teams with tighter budgets typically start with Apollo (or Cognism for EMEA) as the primary data source, add LinkedIn Sales Navigator when social selling becomes a structured motion, and evaluate intent data later when the team has the process to act on it. Buying 6sense before you have SDRs trained to use intent signals in their weekly prioritization is a common way to spend $60,000 on a tool that sits underutilized.
The sequencing of tool adoption matters as much as tool selection. Get the contact data right first — that's the foundation of any outbound motion. Layer in intent data when your ICP is defined precisely enough that "account is researching data enrichment tools" translates into a specific outreach action. And add relationship intelligence (LinkedIn) when social proof and warm introductions are actually part of how your team closes deals.
For individual tool deep dives, see our reviews of ZoomInfo, Apollo, Cognism, 6sense, Bombora, and LinkedIn Sales Navigator. For teams evaluating data enrichment specifically, our B2B data enrichment tools comparison covers the stack in detail.