Well, the game has just received another update (1.05) and after playing it again and again, I've come to the conclusion that Treyarch is absolutely hopeless. They might know how to make good maps, a more or less balanced gameplay experience - but they most certainly are worthless at fixing match making.
Why in gods name does the game match make myself or my party of two with 99% americans which is at closest aprox. 6000km away? And it's not like we're playing in the middle of the night, but in the early evening with most Europeans active? There were 300'000 users online in TDM for god sake.
As a result - unstable connections, laggy gameplay were the result. Stabbing a guy multiple times in the back with a knife only to watch him turn around and shoot you and then watch the killcam present an entirely different game is not fun.
MW2 had its faults, but the matchmaking wasn't nearly as bad as this is. And yes, we did make changes to the option "Local / Local-only". Connections used to be better, but it's become downright terrible the last couple of weeks.