Overall, I thought this movie was fantastic. The finale was one of the most tense I've seen in a comic book film. The finale was getting so bleak and brutal that for a minute there, I was honestly starting to believe that we weren't going to get a happy ending. It's pretty rare when comic book movies can do that nowadays!
There were two things that really bothered me in this movie (hint: they involve Emma Frost and Rogue), and there were some plot conveniences (such as Kitty's powers), but the good easily outweighs the bad. The acting in this film is something to behold, because the actors brought in their A-games. James McAvoy was the standout actor in this; I believe this is his movie. And Michael Fassbender has dethroned Ian McKellen as the definitive Magneto, as far as I'm concerned (I've been saying this since First Class, actually, but this movie further solidifies my opinion).
Also, that Quicksilver scene is probably the single coolest thing I've seen in any of the X-Men movies. He was hilarious and fun to watch. I didn't think I was going to say this, but Joss Whedon has something to worry about for Age of Ultron, because X-Men's Quicksilver was awesome.
This is my favorite X-Men movie to date, with First Class coming in a close second. Twentieth Century Fox deserves some kudos, because I'm excited for the X-Men movies again! As far as 2014 comic book movies are concerned, though, Captain America: The Winter Soldier is still my favorite for now.