I saw it yesterday, and I love it.
I understand the reasons that Alan Moore has disowed the movies based on his stories (From Hell, Constantine. LXG), but sometimes I see him act like a cry baby. I know he works hard on writing those stories and the cinema can't bring all the complexity of his works. But most movies needs to have a broad audience to make money and stories needs to be adapted to reach that audience. So what if they make Alan Quatermain the leader in LXG instead of Mina Hacker, so what if Johnny Deep does look remotly like the real Insp. Abberline, Keanu as Constatine (and Sting would have be better???).
I haven't read the V for Vendetta graphic novel. (I read LXG vol. 1 and look over quicly From Hell) If I find a copy of the novel I will buy it and read all the complexity and moral ambiuguity of the novel. Until then, the movie works for me fine.