I really enjoyed this film; I think we can safely agree that it’s the best X-Men film so far (which I guess isn't saying that much, but it was good, I swear). Above all, Magneto and Xavier were well cast. Michael Fassbender (Magneto) and James McAvoy (Xavier) pulled off some pretty cheesy lines with sincerity and depth, and it actually worked.
The thing that made this film great was that it was Magneto’s story, and you sympathized with and understood a more complex character than a mere villain. All the story development of Magneto’s character and past was interesting, evocative, and well developed. I even enjoyed watching his relationship unfold with Mystique, although I would have preferred that she had refrained from throwing herself at him… and that she was played by a different actress—I thought she was grossly miscast.
Speaking of miscasting, January Jones as Emma Frost drove me nuts. I was shocked that she delivered her lines like a mousy Betty Draper. Even as ‘60s Emma Frost, playing right-hand to Shaw and bending to his every whim, I could never imagine Frost as a soft-spoken submissive, and I didn’t think any of the other women in the film had this problem.
But back to the things I loved. There were a few choice cameos that made my day, but I’ll forgo the specifics. I highly recommend seeing this film in theater for some pretty awesome special effects and shots. Plus, I thought it was a much more interesting story than Thor.
Side notes: there's no extra scene after the credits. Also, upon seeing First Class, several people have asked me for X-Men comics recommendations, and my glowing recommendation is the first four trades of Astonishing X-Men by Joss Whedon. It's a self-contained story arch that features the likes of characters from First Class. Enjoy.