I've been wondering this too since I was in the middle of max prestiging my swat. Post-patch with Silencer doesn't take as much ammo as it did before. I'm still on the fence with SF as I don't really use this at all and find burst firing much better.
I tried Swat with SF yesterday; unlocked suppressor for it in the process and slapped that on. Sweet gun now. Thing is, you can still burst it for long range accuracy (without switching). I had SF, suppressor and stock on this and was destroying stuff up close and med-long range.
If it's true that we learn from our mistakes, then I should be a frickin' genius by now.
I never got the hate for the SWAT anyway. The only problem I ever had with the gun was when you got into a lobby where you can plug someone with three bursts, and they turn around and maul you with one pistol round. In a lobby like that, the SWAT is useless. But that is a connection issue, not the gun itself.
Games that need a new entry: Nightmare Creatures, Fear Effect, Gungrave, BloodRayne, Mirror's Edge