To the few who like to cry.....shut up! THIS GAME IS GREAT!
The additions of being able to jump into games already in progress, and being able to move players around on teams when the room is already full are great. The sprint button adds a whole new demention to the game that definitetly makes it feel more fast paced, especially after the ridiculously fast C.O.D. 4. Also the addition of some retro maps from Rainbow Six 3, Rainbow Six Black Arrow and even from the last edition, were a great idea.
The enemy AI in the campaign is smarter, if not much, than the first game. Just enough to make you notice the difference and slow down just a bit when running through levels. Your AI partners also seemed to have gone to school and learned a little more about not running out into gun fire, although they will still go on these suicide missions and sometimes hide in cover in the not the best spots.
All in all this is a great game, definitely worth buying and playing over and over again with your friends on xbox live!!