The lag is NOT just in online play... it's in split screen coop as well. And yes, i DO know the difference between a jumpy framerate and LAG. Lag causes characters to jump from one point of the screen to the next suddenly... seen it happen in split screen. Originally wanted to blame disc read issues, then realised i was playing from HDD...
Tell me if it fixes it, I haven't turned my 360 on in a couple of weeks because of it. If it doesn't make it any better then I'm trading it in!
Here a list of the patch, source Kotaku. All in all alot of changes/improvements. Any Gears players willing to find out if this is the answer to your woes?! Edit: had the list on this post but it was way to long, I'm sure anyone interested can follow the link. The patch improvements are divided into exploit fixes, balancing, general fixes and improvements (which include new achievements)