Team SWAT isn't half bad but I've been having more fun with Team Snipers. I never used to be able to use the Sniper Rifle very well before giving it a try, but after a few hours of getting your head blown off, you get the hang of it, then it's the most insane test of precision and reflexes the game has to offer.
Even better is going back into the Team Slayer playlist and walking out with Killing Frenzies because you grabbed the sniper and fucked shit up. I can't wait until I can pull of consistent no-scopes. Right now I find myself finding a target, zooming into 5x and getting a headshot but in close quarters that doesn't work too well :/