Among the things that I really liked are the references to the earlier books, particularly the first, to show how far Harry's come since then, the Dumbledore backstory, and the character development of the Trio.

On the less positive side, character development for most other characters is limited and I found it odd that one of the major themes of the series, the way the good guys find strength in love and friendship and cooperation against Voldemort's evil mastermind merely using his DEs as pawns, is essentially thrown by the wayside here. Not only do the Trio cut everyone else out of their plans - only partially reversing that decision at the very end - but then Harry decides to go it entirely alone. Understandable considering the circumstances, but it seems to me a climax in which his friends could play a larger role would've been more fitting. And then of course there's the Hallows and particularly the Elder Wand that I don't much like.

In all, it's a mostly satisfying conclusion to the series, which must've been challenging enough, but I don't think it's as good a book as Half-Blood Prince.