From what I got it's a tie between BF: BC2 and MW2.
Gimme more detailllllssssss
In bad company 2, you can use squadmates as portable spawn points.
Snipers can snipe over distances of 500+ meters if they want to, no such thing as quikscopz 360 dropshoots.
Shotgun's don't have the range of you throwing a 10 ton boulder.
Starting weapons are "ok". (IMO)
Call of Duty is faster paced, yet flows smoothly...in most matches.
Easier to unlock guns and perks.
MUCH faster leveling up.
Starting weapons are pretty good. (again, IMO)