I saw the movie this afternoon. I thought it was easily the second best movie in the series. The third movie only beats it since it was a more complete story, this one really needs to be seen with all of the past movies to be fully appreciated.
Some things I liked:
They did a great job showing Bella first waking up as a new vampire and showing off some of her powers. It was nice seeing her kick some ass. We got many neat scenes showing off the powers of the new vampires in the movie. The Volturi finally do something besides standing around and making threatening remarks. The final twist of the movie was something I expected since I had read the book, but I was glad it was there. If they had completely followed the book there would have many pissed off people in the audience. The action was good if a little too bloodless. The final part of the movie showing the entire cast in black and white was probably one of the highlights for all the Twihards. I also loved the music during it.
Things I had problems with:
The CGI scenes with young Renesmee was very distracting since it wasn't good at all, but thankfully it got much better once they stopped using it for the actress and just let her act. Jacob had almost nothing to do in this movie, but I guess that was a problem already from the books. Also barely any Alice, but I guess she was good at the scenes she was in.
I had a good time. This movie isn't for people that suddenly decided to watch out of the blue, but for those that have been watching the series as it had went along.