I have to say I prefer Claude for code and diagnosis. ChatGPT in CoPilot often replies with essentially, "these are the things I would be looking at if I wanted to troubleshoot this", to which my muttering frustration is, "yeah obviously - no sht - now do it.", whereas Claude just does it (e.g. looks through the code, provides analysis as to where the problem is or the nature of the problem, and returns a practical and immediately useful response). You could say that's a prompting problem (and you'd be right) but if Claude is lower drag than ChatGPT in this context and others, that's a value proposition.

However, I really do* prefer ChatGPT for generalized but as-applied conversation about architecture decisions, pros/cons of different approaches, patterns. Claude can do this too, but I do prefer ChatGPT for this.