I really genuinely disliked First Class. The plot and the pacing were clunky and awkward, Xavier and Magneto were completely passive throughout most of the film (gathering mutants together and building Cerebro weren't even their idea), Beast's subplot was really awkwardly shoehorned in, everyone on the team besides Xavier, Magneto, and the two blue people were complete non-characters who contributed nothing to the story, Angel's decision to switch sides was completely unmotivated and amounted to nothing, the Hellfire Club members switched loyalties cartoonishly easily, Sebastian Shaw's plan was just silly, Shaw's motivation simply being a vague, watered down, dehumanized version of Magneto's politics was weak and fairly lazy, the dialogue was pretty bad, the seams from when different unrelated scripts were chopped up and taped together were really obvious to me, and Magneto realizing the full potential of his power through the magic of Hanukah was the dumbest, WASPiest writing I have ever seen.
The fact that people like this movie as much as they do, and even cite it as an example of brilliant writing and one of the best CBMs ever, is genuinely baffling to me.
Now, of course, none of this is to say that the movie is putrid and offensive. It's not. It's just kind of incompetently put together and really really lame.
Oh, and Wolverine's cameo sucked. It was just pointless fan service that took me out of the film.