Personally I've found it's very good at writing support tools / shell scripts. I mostly use it to parse the output of other tools that don't have machine-readable output yet.

Claude Code (which is apparently the best in general) isn't very good at reviewing existing large projects IME, because it doesn't want to load a lot of text into its context. If you ask it to review an existing project it'll search for keywords instead of just loading an entire file.

That and it really wants to please you, so if you imply you own a project it'll be a lot more positive than it may deserve.