Peaceful Jay is currently streaming and demonstrating that 360 netcode is indeed ass. It looks like it runs at like, half-speed. No joke.
It being so bad compared to the PS3 version is probably good news in terms of it being fixed and back to being equivalent with the PS3. That is, it's something obvious to them and not just a subtle difference from the PS3 version that they can't seem to figure out if that makes sense.