Betsy, it was very satisfying. Rowling has laid in so many plots and subplots in her books that it's amazing she was able to bring them to a satisfying conclusion. I know that there is always advertising hype like "this book/series is the next Harry Potter!" but I don't think such a thing is possible. (And I hope not, since I'd rather be a great writer of my own, instead of just a next Somebody Else, wouldn't you?) But seriously, this...series, or story, is different. And I don't mean because of hype and advertising. I doubt anyone will achieve such a complicated yet satisfying story for a long, looooong time to come. What I continue to find astounding is that it's all there in book 1. The whole story, sort of in zip form. Even all the way down to the last book, there were so-called background details from the very first book that ended up being very significant to the entire plot. It's more than just keeping a list of what color eyes different characters have, or what houses they're in or whatever; it's keeping track of motivations, backstories, interactions that is something that JKR does extremely well. I love her ability to surprise (and since she's able to pull it off for more than one book, she's rather good at it). She's very good at giving you what you think is the truth--and it is, only it's not the whole truth, and time and again, she's able to surprise the reader by giving more of the truth at the right moment, and suddenly you find yourself restructuring the story into something completely different. She's created so many characters to care about, and she cares about them, too, following up all of these little stories, like Kreacher the unhappy house elf, or Neville's relationship with his gran.
Regarding the epilogue--I think it had a number of reasons for being there. First, a zillion readers are going to ask, anyway, so why not just print up the answers right there, and save breath? Second, it settles once and forever the notion that there will be some kind of book 8. No. No, no, and no. There is No Tension Left to stand a book on. No, the epilogue isn't necessary; the story ends find without it. But it's just nice to know what happens.
And regarding mixed reader responses...some of those readers raced through pretty fast. There's a lot in there. I suspect that reading the book by day, at a more normal reading pace, yields a somewhat different response than wolfing it down in one bite.
Something else I enjoyed--sometimes the myth or thematic overtones of a one-of-a-kind book can get a little too big. I'm sorry, throw tomatoes at me, but at some point in LOTR I couldn't really relate to Frodo anymore. His experiences and ultimate challenge were so exalted and so far removed from me that just couldn't keep the connection. Instead, it was Sam who was Everyman, Sam who I found I could hang out with. All of which made the reading experience a little strange to me--the key character being a bit on a pedestal. Despite all the climactic events of HP, though, I never lost touch with Harry. He's heroic in so many ways, yet he's always human and imperfect and vulnerable, and so we can still relate to him.
Also, I found the ending very happy and uplifting. Death isn't something to fear, it's not the End, it's the "next great adventure," to quote Dumbledore. The dead are there, waiting for us. At the same time, the living are alive, too, and those still alive at the end really could rejoice. This wasn't one of those books where the Hero conquers Evil and thereby does away with magic and now everyone lives like a Muggle. Instead, miracles happen, and we can rejoice in that magic.
Themes I loved:
miracles and magic
second chances
gifts, and yet the importance of our choices--such a very big theme
hope
love
Cheers to Harry Potter--the Boy Who Lived!