I play hardcore and most times the other team is a party. This always causes really bad lag to the non-party side guranteed 90% of the time, Ive played games were my screen would freeze whenever the other team is in front of me and they can just shoot me down like a sitting duck. This constitutes cheating according to Xbox policy as it gives one side a known advantage. I always report them. </br>
Besides this problem Black Ops is a great multiplayer.