I've been playing Call of Duty 4 for 360 and ps3, and I can say there is nothing like whats going on with the ps3. I can barely play the ps3 version anymore. I don't have MW2 on the ps3 though, so I can't say how bad it is.
The PS3 board is in hell right now, and I've run into two or three hacked lobbies yesterday. The first was on Strike where this guy on the other team was 100-2 when I came in, and when I spectated, it look like his AC-130 had an 105mm gun that could constanly be spammed. Along with it were mega high jumps and super speed sprints. Another lobby was on Rust (it was more of a secret game mode) with two teams, and every time you spawn you "roll the dice". Depending on what you get, you will get something that hinders you or gives you some crazy ability.(eg,unlimited ammo or bulletproof) I will say both lobbies were tons of fun though.