Worst multiplayer I've ever played, but a pretty good campaign and side missions, nicknamed "Special Ops".
Seriously, the multiplayer online is terrible. Nothing but campers, "pros" with instant kill weapons that you must sacrifice your virginity for, and 6-year old children screaming at there mother to get them some chocolate milk.
Bob: Hey, you play Modern Warfare 2?
Tom: Yeah, the campaign is awesome, so are the side missions.
Bob: You tried multiplayer yet? I'm already a 3rd prestige level 65!
Tom: Nah, the multiplayer is pretty noobish. I played with some 7 year old who kept camping with the Akimbo Rangers.
Bob: Yeah, I hate those little bastards.