I am unclean, don't speak to me! I've read the last of the Harry Potter books, and I dare not give away any of its secrets, even by glancing the wrong way when you talk to me.
More seriously, it was a rousing good story, and was satisfying to the end. This book felt much more edited than the last few. The writing was tighter, sometimes cinematically grand, without losing her touch. But there was less that was extraneous. In fact, it felt like a 1,200-page book that had been greatly trimmed. Given Rowling's native abilities, I could truly believe that she worked with multiple trusted editors to get the thing into the right size. She must have been hard pressed to leave things out. There's so much more.
This book had a lot more elements creep in that reminded me of Lord of the Rings than any of the others. The coincidence of a gray-bearded wizard who speaks in riddles and knows more than he ever says isn't a strange one (although it was hilarious when you had Harry Potter and LotR movies released at the same time). This book is about war, although it's a bit of The Scouring of the Shire (last part of the LotR), the war in Rohan and Gondor, and the trip into Mordor, all at once. Old J.R.R. was an epic writer, and so he separated his scenes widely, which helped make for good movies, too.
I wonder if she will write prequels now? Books of Harry's father and mother? Books about the founding of Hogwarts? Or will she enjoy having written a set of books that will be read into the foreseeable future, and enjoy just being an exceedingly wealthy mum?