Pros: bigger world, great storyline, major character interactivity, non-linear gameplay.
Cons: none, as far as i know.

Had played GTA vice city before this and loved it so much that i thought nothing could be better until i came across San Andreas, which made vice city look old, love the characters, especially the main one, CJ and OG loc, love the story line, the freedom in the game to do anything. Love the way the gameplay is different for everybody, no two CJs even look the same.