I'm a fan of HP. Enough of a fan to read and write fanfic and attend a convention.
That said, I don't think Rowling is the greatest writer ever; if you approach her style with a style guide in hand and start looking for all the things that are "technically wrong", you'd find plenty.
There were also a lot of things in the books, plot-wise and character-wise, that didn't sit entirely well with me. I don't agree with her on a lot of issues; I didn't like the way she treated some characters and topics.
All that aside, I think she's an amazing storyteller and has an amazing talent at world building. And I'm very clearly not alone in thinking that. Not one single book in the world can be loved by everyone, and every person has different tastes (I don't like or am not interested in plenty of other popular books), but I do think it's an unarguable fact that there is something in Rowling's writing that worked for readers. Millions upon millions of readers. (And hype can't account for all of them - the hype had to start from somewhere, after all.)
Will I read her new book? I don't know. I'm not going to declare anything, one way or another, before more is known about it. If it's in a genre I like and the description sounds at least somewhat appealing, then yes, I'm pretty sure I'll give it a go. It may suck, or it may be wonderful. If it's in a genre that doesn't appeal to me, or if the description leaves me completely cold, I am not going to read it just because it's Rowling.