No reason for a review here - there's plenty floating out there already... what I will say is the following:

+ I got an advanced copy through pleading, so I'm already 6 hours into the game and have been enjoying it. A lot. And I've only seen spots of 1/3 of the overall map.
+ The game play is exactly what I've loved GTA and Bully for
+ All of things that I used to dislike about the game are gone in this release (GPS nav rules, auto-saving after every mission, easy health restoring)
- Niko is one slow moving bastard; praise the A-to-Run button
+ The graphics work is simply amazing, even by 360 standards; best thing T2 could have done was release the retro-feeling Bully two months ago...

I've heard there's multiplayer too, but in all honesty: I can't get away from the story yet.