I find they achieve acceptable, but not polished levels of work.

I'm not even a designer, but I care about the consistency of UI design and whether the overall experience is well-organized, aligned properly, things are placed in a logical flow for the user, and so on.

While I'm pro-AI tooling and use it heavily, and these models usually provide a good starting point, I can't imagine shipping the slop without writing/editing a line of HTML for anything that's interaction-heavy.