X-Men: First Class had very good pacing and I liked the story. The actors did a very good job, the director also did well in my opinion, and the effects were well done as well.
The only three things that I did not especially like: 1- The whole "Mutant and Proud" thing was far too cheezy and just ruined several parts of the movie. 2- There's no little clip after the credits. I think that kind of thing is just expected for action hero movies (especially Marvel). 3- From the first three movies I thought they said Magneto and Professor Xavier built Cerebro together. Well, in this movie don't and I didn't really feel that this prequel matched up with the other three as far as continuity goes other than bringing back some of the actors. But hey, I think they used the same mansion.