Claude Code is much more aggressive at doing stuff than aider is (with sonnet and gemini) in both good and bad ways. You can tell Claude to do a thing and it might churn for many minutes trying to achieve it, while aider is much more likely to do a lot less work then come back to me. Aider feels more like a small sharp tool vs Claude Code as a bulldozer.

They both can just use api credits so I’d suggest spending a few dollars trying both to see which you like.