I played a little MW3 but not much online, didn't play any Black Ops. I used to play SOCOM back in the day, and this is nice because the time between rounds is short.
There's a contextual lean, that will lean you around a building/wall/tree if you're aiming down the sights.
I like the maps, there's a wide variety of sniper rounds, run and gun rounds, and some in the middle. It feels like a pretty balanced game to me.