X-men: First Class is only the second x-men movie I've watched (the other being the original one) so I can't really compare it to the other movies in the franchise. But I will say that I really enjoyed this movie. In short it is about younger versions of Magneto and Professor X assembling a team of young mutants to stop another group of mutants from starting a war. Now on to the content. WARNING! I'll try my best but there may be SPOILERS!
Violence - 7/10
For the most part the violence is just like any other comic book movie, shooting, punching, explosions, and using unrealistic powers all without any noticeable blood or gore. But there are a few exceptions. As a boy during WW2, Magneto was taken away from his parents in a German concentration camp, this is scene in the opening scene which ends with a Nazi slamming the butt of his gun into Magneto's face. This scene is very emotional. Later, the villain, a leader at the camp tries to force Magneto no use his power by threatening to shoot his mom, and ends up shooting her. Its in the background but its very sad and disturbing. At the end Magneto kills the villain (who is frozen still) by using his powers to force a coin through the front of his head and out the back, all on screen. If this happened fast it wouldn't be so bad, but they make a big deal about it and it happens very slowly and clearly.
Sex - 6/10
I was surprised by the sexual content in this film. No actual nudity but most of the women in the movie are strippers at parties who wear very skimpy under ware. Lap dances are suggested and in a very quick scene you see a woman in her bra sitting on a man's lap, him kissing the top of her breasts.
Language - 6/10
mostly mild, d*ck, d*mn, h*ll, Jesus as a exclamation, with the exception of Wolverine's cameo where he tells someone to "go f*ck themselves.
Overall interesting movie with some sexual content.