Here’s a concise comparison of Capterra, G2, and Software Advice to help you choose which to use (as a buyer researching software) or where to list/promote a product (as a vendor).

High-level summary

• G2 — Most review-heavy and product-comparison–oriented. Strong for mid‑market & enterprise buying research, side‑by‑side comparisons, and sentiment analysis. Good for visibility and conversions if you target SMB to enterprise buyers.
• Capterra — Broad directory focused on small-to-medium business buyers; easy browsing by category. Great for discovery and simple shortlists; often drives lots of leads for vendors.
• Software Advice — Sister site to Capterra (both are part of the same parent company, used to be Gartner Digital Markets). Focuses on buyer guidance and lead generation via phone/email consults; more consultative approach for SMB buyers.

Audience & buyer intent

• G2: Buyers who are comparison shopping, want detailed peer reviews, product-market fit signals, and feature-by-feature comparisons. Often mid-market and enterprise buyers plus technical evaluators.
• Capterra: Buyers earlier in the funnel or SMB owners looking for quick options by category, price, and key features.
• Software Advice: Buyers who prefer hand-holding — they’ll often request a consultant call or vendor introductions; good for buyers who want a guided selection.

Reviews & content quality

• G2: Large volume of reviews, with verified-user badges, Q&A, and detailed review fields (pros/cons, ROI, use case). Review quality tends to be higher and more structured.
• Capterra: Reviews are usually shorter, simpler, and straightforward — useful for quick social proof and star ratings.
• Software Advice: Reviews similar to Capterra (often shared across the same platform family); plus buying guides and analyst-style articles.

Search & discovery features

• G2: Powerful filters (company size, industry, features, reviewers’ role), robust comparison pages, product grids, and trend/market reports.
• Capterra: Clean category pages, good filtering by features and pricing, intuitive for nontechnical buyers.
• Software Advice: Category pages plus the ability to request consultant help and vendor matchmaking.

SEO & traffic (vendor perspective)

• G2: High organic traffic for product + comparison queries; being visible on G2 helps competitive positioning and enterprise credibility.
• Capterra: Very strong for category searches and SMB buyers; often produces high-converting leads.
• Software Advice: Generates inbound leads via consultative matching — fewer raw visits vs G2/Capterra but higher intent for direct contact.

Lead generation & cost (vendor perspective)

• G2: Offers paid placement, enhanced profiles, and lead programs. Leads can be higher-value but more competitive/expensive.
• Capterra: Pay-per-click (PPC) model for leads in many categories; historically good volume for SMB-targeted products.
• Software Advice: Lead-gen focus with consultative connections — often costs per lead and can be efficient if your product matches SMB needs.

Trust & moderation

• G2: Strong verification mechanisms, review gating controls for vendors, and robust reporting of fraudulent reviews.
• Capterra/Software Advice: Also have verification and moderation; because reviews are simpler, potential for brief or less detailed reviews exists, but both maintain anti-fraud policies.

Use cases — which to pick

• If you want in-depth comparisons and influence technical/procurement buyers: prioritize G2.
• If you want volume of SMB leads and strong category discovery: prioritize Capterra.
• If you want consultative, high-intent buyer introductions (phone/email matches): prioritize Software Advice.
• Best practice: use all three if budget allows. They reach complementary buyer segments and the same parent company ecosystem provides cross-listing benefits.

Practical tips for buyers

• Read multiple reviews across platforms to get a rounded view (G2 for depth; Capterra/Software Advice for breadth).
• Filter reviews by reviewer role, company size, and recency.
• Use G2’s comparison and grids to shortlist; use Capterra to find niche vendors; use Software Advice if you want a consultant to pre-filter vendors.

Practical tips for vendors

• Maintain complete, up-to-date profiles on all three.
• Encourage authentic customers to leave detailed reviews (G2 reviews with problem/ROI details perform best).
• Monitor review sentiment and respond publicly to reviews to show customer care.
• Test ad/lead packages and track cost per lead and conversion — pricing and ROI vary by category and target market.

Limitations

• All three can produce biased samples (reviewers are self-selecting).
• Paid placement can favor vendors with higher marketing budgets; don’t rely solely on these sites for reputation — also invest in case studies, references, and other channels.

If you want, I can:

• Recommend which platform mix is best for a specific product or buyer profile (tell me target customer size, industry, and budget), or
• Create a short checklist for optimizing a vendor listing on one of the sites.