It does really well when I'm telling it to refactor existing code. But it's nearly unusable when you ask it to generate freeform code.
So now I made a prompt that forces me to write up a first draft myself, then work with the AI to refactor.
I saw someone say something about how AI is great to get you started, but has diminishing returns. I'm going to try and see if not using AI much in the beginning will give it more value in the long run.