Well, last I checked Claude's webchat UI doesn't have LaTeX rendering for output messages which is extremely annoying.

On the other hand, I wish ChatGPT had GitHub integration in Projects, not just in Codex.

I've also had Claude Sonnet 4.0 Thinking spew forth incorrect answers many times for complex problems involving some math (with incapability to write a former proof sometimes), whereas ChatGPT 5 Thinking gives me correct answers with formal proof.