Let's get our stuff clear for a second here.
Kick-Ass (as in the original comic book) was written by Mark Millar, who is quite popular for reasons I know not. He's not a terrible comic book writer, but I'm not a huge fan of his stuff. Civil War was kinda wallbanger-inducing (wait, we're SUPPOSED to root for the totalitarian Pro-Reg guys?), Giant Size Old Man Logan was all right, if only for the use of a cow as a weapon and that's pretty much all I've read. Hollywood is a big fan of his stuff (for example, Nemesis is only about 1-2 issues in, and it's already being optioned for a movie adaptation), despite the fact that Wanted was a bit of a flop. Kick-Ass 2 is being worked on as we speak, and I won't be surprised if it too will get a movie sequel.
MEANWHILE, V for Vendetta as written by Alan Moore (writer of y'know...WATCHMEN) did have a message, which is that extremism, be it by anarchy or fascism is a very bad thing. However, Hollywood being Hollywood, kinda messed it up and turned the original plot into something reminiscent of 1984. It wasn't all that bad, but they did screw up a few things (V wasn't a morally superior resistance fighter, he killed innocents in his way; Creedy just wanted to be loved, etc.)
TL;DR
Kick-Ass = crazy stuff happening left and right with some humor, story translated well onto big screen.
V for Vendetta = deeper stuff going on, has a message that got lost in the adaptation.
