The controls take some used to, especially the new aiming method for thrown items (although it does give you an insane level of control). It'll take a while before the gamespeak commands are burned into my brain, although the quiksave feature is a fantastic addition to the game. The graphics are great (like the new little background features) and it has rumble too!
The UXB mines seem a bit strange/difficult at the moment (again, thank heavens for quiksave).