1) It often overcomplicates things for me. After I refactor its code, it's usually half the size and much more readable. It often adds unnecessary checks or mini-features 'just in case' that I don't need.
2) On the other hand, almost every function it produces has at least one bug or ignores at least one instruction. However, if I ask it to review its own code several times, it eventually finds the bugs.
I still find it very useful, just not as a standalone programming agent. My workflow is that ChatGPT gives me a rough blueprint and I iterate on it myself, I find this faster and less error-prone. It's usually most useful in areas where I'm not an expert, such as when I don't remember exact APIs. In areas where I can immediately picture the entire implementation in my head, it's usually faster and more reliable to write the code myself.