I saw this a few days ago, thought it was really funny. I still want to read the books, since I know a lot had to get cut out to fit 6 volumes in 2 hours, but standing alone it did pretty well.
The accusations of twilight for boys miss one of the important differences. In Scott Pilgrim, Scott and Ramona are both flawed characters, their struggle involves trying to screw up less and fix their messed-up lives. Bella and Edward are presented as perfect, even when they quite obviously are terrible people.
Oddly enough, my biggest problems with the movie were music-related, Stephen Stills' acoustic sounded like an electric, and I'm pretty sure I noticed other things while i was there. And was I the only one that heard what sounded like an instrumental version of Black Flag's Nervous Breakdown during the random fight right before the Gideon fights? That wasn't a problem, though, just a surprise.