It was enjoyable while I was reading it. I giggled at a few points. Unfortunately, as I was afraid it would be, the book could easily have been titled Harry Potter and the Overrated Scavenger Hunt. Killing random (minor) characters did not build up the tension for me though, it built up a tally counting mentality instead. It begs for drinking game, similar to what Dr. Pain suggested yesterday as we were walking around London: "You could carry a pint glass with you, and every time you passed somebody walking while reading Harry Potter, take a drink. You'd get slaughtered." Of course, you wouldn't get so slaughtered reading a 600 page book. That's okay, random characters get slaughtered instead.
And speaking of random character deaths, seriously! What? Does Rowling have an obsession with orphans? This has probably been said by a lot of people already, but the killing off of father figures is completely overkill. I was saying before I read it that I'd be annoyed if she killed off Lupin because she's already killed off all the father figures and it would serve no good purpose, and she went and did it. Lupin wasn't even father figure-ish enough for it to make any sense at all (do we need to kill off the uncle figures as well?). Killing Hagrid would have had much more emotional impact for Harry, and his continual escaping death got really bloody annoying. And what was the point in creating little Teddy Lupin and then orphaning him right away? (As a corollary, Twin != surplus. Talk about being predictable though.)
Thematically speaking: I'm glad that Snape held up somewhat as a character that proves nice and good aren't the same thing (although, bits of that reminded me of some seriously annoying fanfic). Sacrifice remained a central and important theme, and things Dumbledore said about the importance of Love became more concrete. (Yay!) The social commentary either got dropped completely or seriously oversimplified into pointless caricature. (Boo! Another reason that killing off Tonks/Lupin was pointlessly sucky.) What on earth happened to "All the houses need to band together"? Absolutely no Slytherin students willing to stand against Death Eaters? (Boo!)
Things that went clunk: Scavenger Hunt (I was afraid that would happen). Late fifth-act planting of guns on mantelpieces. Excessive expository letters, diaries, books, etc. Almost everything to do with Remus Lupin. Ginny. Unrequited Love!Snapey-Sue. The Doe Patronous. Death Defying!Hagrid. Unforgivable Curses: If an Unforgivable is "unforgivable," why are all the good guys suddenly using it?
Things that made me happy: Neville. Luna's bedroom ceiling. How to get into the Ravenclaw dorms. Aberforth Dumbledore. Potterwatch. "Ear, Ear!" (I'm easily amused.) Percy. RIP!Dobby. (I just didn't like him.) The fact that George lost an ear because Snape was trying to save Lupin. Minerva McGonagall.
I'm sure there's more to say regarding the book itself, but that's it off the top of my head. The big thing that makes me immensely happy is that there's a book creating such an avid readership. I've never thought the books were much better than fun fluff with likable characters and a fascinating fandom. (I came to the books as a fanfic addict, not the fandom as a Potter addict.) As a series, it's horribly uneven. As Fantasy, the world building is incredibly messy. But to begin with, the books got kids reading. Then, it got lots of adults who disdained "Kids books" or Genre fiction broadening their selection a bit. Then I heard a story from one of my students whose little brother was begging for glasses, not being made fun of for wearing glasses. J. K. Rowling has made wearing glasses cool. And, until this weekend, being a person who was in danger of walking into a lightpost because you forgot to look up from your book put you in a very small (and often ridiculed) minority. J. K. Rowling has made reading cool. This, no matter what your opinions of the books actually are, is incredible.