Stylistically, Sin City is one of a kind. I am a fair-weather fan of stuff like this, but Sin City was really refreshing. It added lots of over the top action/violence and it was done by a great cast of convincing people.
However, I felt the film was both too short and too long. It was too short in the fact that (correct me if I'm wrong) there were a TON of characters introduced but most of them weren't expanded on. I would have liked to see two or three movies fleshing out the characters, with each movie following a more cohesive storyline.
The movie was too long in the fact that it was disjointed. No sooner did I stop reeling from one ending when another beginning came up and I didn't have time to sit back and appreciate what had just happened. And, for some odd reason, about 2/3 through the movie, my internal clock kept telling me the movie should end.
Then again, pretty much everything is absolved upon seeing Jessica Alba in a cowgirl outfit.

I think this is a movie that needs to be watched a few times to be truly appreciated (like Pulp Fiction), so I look forward to a DVD release so I don't feel to pressured ot take so much in at once.