Where the incumbent tool wins, where a pay-per-use actor wins, and which one fits your workflow. Written to be fair, not to sell.
eRank is a subscription keyword-research and listing-audit dashboard at $9.99 to $19.99 per month. Etsy Sales Intelligence is a pay-per-use API actor focused on revenue estimation at $0.05 per listing. Feature matrix, pricing and use-case guide.
Terapeak is free inside eBay Seller Hub but needs an active seller account and has no public API. eBay Sold Listings Intelligence needs no eBay account, returns JSON via API and costs from $0.05 per run. Feature matrix and data-depth comparison.