I really dug it, but I think the comic was slightly meaner and better (Big Daddy's origin in the comic is darker and funnier - but I loved the origin in the movie with John Romita Jr.'s art, the resolution of Dave's relationship is way better and unexpected in the comic, the Hit Girl doing cocaine aka "Code Red", Red Mist & Kick-Ass going into the burning building was crazier in the original, Dave doesn't kill anybody in the book and that's kind of the point). But this isn't without it's merits - had a lot of funny stuff, some great music (wiki sez they cribbed the cue in the warehouse from Sunshine), and Vaughn's direction was very interesting to watch - and even improved on a few aspects. The movie diverges slightly in the end but that's probably because the comic took forever to come out. Still a very good movie and a very good adaptation, way better than the hack job that was Wanted.
For those interested in the comic, get your torrent on