I just got back from seeing this movie and I agree. It IS the best superhero movie ever, at least in terms of originality. Iron Man 2 has some really tough competition here with Kick Ass. This was one of the most well-paced comic book movies ever, the dialogue was dirty and fun, the jokes had me laughing every two minutes. The acting was great and the R rating is definitely unrelenting.
This movie has a lot of controversy surrounding it. And it definitely lives up to it. Especially surrounding Hit Girl, who curses like a sailor and shows no mercy to grown men. The casting was also great, having a newcomer playing the lead role, a high school geek who becomes the superhero Kick Ass. Then there's the father daughter duo, Big Daddy played by Nicholas Cage(who does a surprisingly good job in this role) and of course Hit Girl.
Kick Ass is colorful and fun, and the movie's story is VERY well-paced and I never got bored at any point from it. The originality of the movie's jokes ranks right up there with the Hangover as we see more comedies, as well as movies in general, starting to break the mold and go beyond what some people find suitable. Overall, this is one of the most original superhero movies I've ever seen and if people can take gratuitous violence and Superbad-level comedy, especially from an 11 year old girl. Then I highly recommend it. I can just imagine some middle-aged soccer mom accidentally taking her little kids to see this and getting a heart attack from it.
Overall rating I give this movie is a perfect 5 out of 5.