Geek wet dream. If you're familiar with Frank Miller's work on the graphic novel(s), then you know what to expect. It's high style, egregious violence in a land where all the hookers have perfect bodies and movie-star smiles, and all the men are ruggedly handsome or ruggedly ugly, and honor reigns in the seedy underbelly of the dark city. It's noir on steroids, cranked up to an earth-shattering 11 and dropped on your senses like a nuclear barbecue grill.
The style captures Miller's work in excruciating, almost fanatical detail. It's not so much a film as it is a live-action graphic novel, or a series of short novellae.
I have not liked Sin City nearly as much as the Dark Knight, which was my first exposure to Frank Miller. Sin City to me has always been a very heavily filtered work, lacking in a certain dimension that I usually enjoy-- but the artwork and style has always been impressive.
The movie carries that forward. It lacks depth of character: everyone in the film is a very stylized character, very two dimensional. I believe that is intentional; the characters are less people and more icons, symbols of a concept that flows within the story. Archetypes.
So if you are expecting something with a lot of depth and emotion, you will be disapponted. On the other hand, if you're looking for a geek-happy rendition of some wonderful Frank Miller work, you will thoroughly enjoy yourself.
Me, I give it an 8/10. I may have enjoyed it more if it weren't for the dextromethorphan-induced haze.
Don't take your grandma.