I love this game, I absolutely do, but I've only had it for a few days, and I've rage-quitted to Modern Warfare 2 twice because of this annoying bug.
I can't even get into a free roam session for more than a minute, tops, before I get the alert that tells me connectivity issues booted me out. I was in a posse with friends, and when another one joined, one of the other players got booted. When he rejoined, the guy that just joined got booted.
In addition, there's that equally annoying loading screen glitch, where you're stuck at the loading screen forever. For me, it always seems to follow being booted from xbox live. I'll have to exit to the dashboard, and because of my crappy xbox, I might have to eject and close the tray a few times before I can play again.
I know there's a patch in the making, but it can't come soon enough. Luckily, I still have alot of single player action to finish.