So I've played a little more than 2 full days of MW2 and all I have to say is awesome. This game truly brings a more cinematic experience to video games. It truly evokes an emotional response from you as you see true character development happen. The campaign is phenomenal. I am still working on it on Veteran but I am half way done on Veteran.
Where this game, and any FPS nowadays, truly excels is in the multiplayer. The ranking system is pretty much the same only there are 15 more ranks you can get to (bringing you to 70 instead of 55) and you can still prestige (rerank up again) 10 times. There is more incentive this time though as you can get extra custom class slots so you have more customization at your fingertips.
All in all this is a very solid game. I feel it is a true sequel to the first game and they made many improvements.
My full review to come soon.