Which AI research tool should I actually use: ChatGPT, Claude, Gemini, Perplexity, or Grok?

There is no single winner: ChatGPT is the strongest all-rounder with the deepest research reports, Perplexity is fastest with the cleanest citations, Claude excels at long documents and careful reasoning, Gemini is generous with deep research and lives inside Google Workspace, and Grok pulls live data from X. Most founders settle on one daily driver plus Perplexity for sourced lookups. Run the same real question through two or three free tiers and pick based on your own work, not benchmarks.

A quick orientation. The real value is below: resources worth your time, from people who've actually done it.