I've had good games, mostly bad as of late. I run an upgraded cable isp. Generally 75/10, ping from east coast to west in around 80ms (sounds a lil high, but maybe not, it IS pretty far). I've had games where I can't miss, and games where I can't hit. No consistancy what so ever. I'm hoping they give this a little more attention than they did in MW3. I'm thinking it's the match making though. I'm fairly consistantly put in lobbies with people speaking other languages. Sure, it's possible that people live near me are speaking french or portuguese, but probably not. They had issues in the past with people in other countries not able to get games, so they expanded the match making. So I guess you can blame the lag on the popularity of the game.
you only need 650 Kb up to play MP, anything more is wasted.