Guys im on PS3 Update 1.05 i NEVER Freze or LAG Its U Not 3arc
Freezing mid-game only occurs when you are host, which means anyone with a decent upload speed gets chosen to host thus causing only a select few to freeze.
If like me, you freeze mid game, I recommend you back out of the game if you're host. Host always connects to the game 1st, so if you press select and every other user is still connecting you know you're host.
Also do the same if the host migrates during a game, look to see if you're host by looking at the bars, 4 bars and chances are you'll be host.
As for the "Its not Treyarch, its you" comment, could you care to explain why I've had no issues hosting in CoD4, WaW & MW2?