Research depth
Discovery
How well the tool supports keyword, competitor, SERP, backlink, or market research before execution.
SISTRIX
Very deep proprietary SEO and AI datasets with history and multiple research modules.
Keyword Discovery offers billions of search queries; competitor analysis combines keywords, visibility, traffic and links; AI Search uses about 25 million evaluated prompts. https://www.sistrix.com/google/keyword-discovery/ https://www.sistrix.com/google/seo_competitors/ https://www.sistrix.com/support/handbook/sistrix-ai-chatbot-research-tool/ai-search/
SpyFu
Broad historical competitor SEO/PPC dataset and many research views.
The homepage says users can see competitors' SEO/PPC keywords and every ad they have tested; https://www.spyfu.com/