Skip the roundup apps. The five most useful apps for comparing AI tools are the candidates themselves. Install them, run them through the same five prompts, take honest notes: nothing beats hands-on. - The ChatGPT app: the safe first download, most features, most polished mobile experience. - The Claude app: the writer's pick, clean interface, strong long-document handling. - The Gemini app: ships on most Android devices already, home-field advantage with system integration. - The Copilot app: the sleeper for Microsoft households, a quiet overachiever. - The Perplexity app: wins any round where citations matter. An AI tool comparison quiz app on iOS or Android can be a fun warmup, but your own test drive is the verdict. Score speed, quality on your specific tasks, and how much you like the app. StackAudit recommends the optimal 3 to 5 tool AI stack for your profession with pricing and setup guides for $4.99 one-time unlock.