I've been using it for a personal project, and it's been wonderful.
It hasn't written a word for me. But it's been really damn helpful as a research assistant. I can have it provide lists of unexplained events by location, or provide historical details about specific things in about 5 seconds.
And for quicky providing editing advice, where to punch up the language, what I can cut, or communicate more clearly. And I can do that without begging a person for days to read.
Is it always perfect? Not at all, but it definitely helps overall, when you make it clear to be honest, and not sugar-coat things. It's definitely mostly mediocre for creative advice, but good for technical advice.
It's a tool, and it can be used correctly, or it can be used to cheat.