Another thing Bad Company 2 Onslaught is good for is trying out higher controller sensitivity. I pushed mine all the way to the top and it’s great!
Granted, I’m playing on easy so it only takes 1 or 2 bullets to take down an enemy but it’s amazing how much fast aiming down sight is. Got into a good game on Isla too, just missed beating my previous best score by 1.1 seconds!