This book ended the series well. Very little trace of whiny and emotional Harry from Half Blood Prince remains - evidently, Dumbledore's death at the end of that book was enough to vault Harry out of the teenage angst he struggled with through most of that book.
I have to be fair - out of the whole series, in this book, the Campbellian themes are stronger than they've been since the beginning of the books. Harry is quite a little “Gary Stu”, and I'm still disappointed that a woman, writing a story that started out as a tale for her daughter, would make so few female characters to identify with, and to keep those as “the girl sidekick”, “the mother”, and “the girlfriend” is disappointing.
Still, anyone who's picked this series up expecting high-brow literature should expect to be disappointed. It's not. JKR is a good storyteller, and the end of the story managed to prove nearly all of the theories about how the story would end right.
I'm actually hoping - as good of a storyteller as she is - that her next series is about completely different people doing different things in a different world. I've heard some suggestions that she should write about the next generation of wizards, but I think that's overkill. Let Harry's story end here and let the fanfic writers go nuts with the next generation.