I use it mainly to tweak things I can't be bothered to dig into, like Jekyll or Wordpress templates. A few times I let it run and do a major refactor of some async back-end code. It botched the whole thing. Fortunately, easy to rewind everything from remote git repo.
Last week I started a brand new project, thought I'd have it write the boilerplate starter code. Described in detail what I was looking for. It sat there for ten minutes saying 'Thinking' and nothing happened. Killed it and created it myself. This was with Cursor using Claude. I've noticed it's gotten worse lately, maybe because of the increased costs.