I just finished reading the book this weekend. Picked it up a while ago at Chapters; and I've been terrified of reading it in case I hated it, and by extension, Jo herself.
Without spoiling anything, I can honestly say that she is as good a writer as ever! The book really surprised me with its content and I had no idea where she was going with the plot at first. I was really frustrated that I couldn't see the thread of the story, but about a third of the way through the book I decided to just slog on and I was rewarded The characters are so well drawn that they stayed with me long after I put the book down. I think my frustrations stemmed from what was happening to the characters, I felt so much that I wanted things to go a certain way for them and when it didn't pan out I got all frustrated.
I must say that if anyone other than JKR had written this book I would have never picked it up because it's not my style; which may be why it took me a while to get into it.
Overall I'd recommend it.