In the past week or so I've been having serious issues with MP in this game on the 360.
Constantly having problems fetching my online profile, can't connect to server messages.
During matches I've been getting a lot of lag which I haven't really had before.
The match making seems to have gone totally bonkers(which may account for the lag). I live in the UK and today I was in a lobby with 3 people from the USA and 1 from Chile. The other day I was in a lobby with 4 Brazilians
Up until maybe mid december this game had been fine for me. It's like the last update messed something up.
Someone else brought up the profile issue. What was suggested to me was 1) do not join a party until you have gone through the Main Menu screen into Multiplayer first and 2) let the multiplayer screen fully load before doing anything else. This may take a while. For me it takes easily a full minute.
Once you do that, then you can join parties or go into multiplayer matches no problem.
Obviously there is some sort of bug causing this and hopefully they'll give it some attention.
As for the lag, what I'm seeing is that it happens when people start leaving the lobby.
As for getting into lobbies with people from so far away, are you absolutely certain your NAT is set to Open? My bro was having similar troubles until I fixed it for him.