lol - I just did some math. Trueskill's definitely in use in this game.
Last week, I went into Matchmaking with mastrbiggy, Slightly Live, and ncsuDuncan (Daedalius joined us for the last couple of matches, too). I played 16 games with the group.
During this run, I went an astoundingly-bad 136 and 237. It brought my K/D down from about 1.6 to 0.85 or so.
Since then, I've played another 20 games or so on my own - so I'm now getting matched up against people who are more or less on my level. My overall K/D has climbed back up to 1.07. If you remove the 16 games played with GAFfers that night, my overall K/D is 1.4.
Playing with people that far out of my league matched me up against people equally far out of my league, and I died almost twice as many times as I killed.
Playing with people in my rough skill range lets me do a bit better than trade kills, and that makes me happier than getting DESTROYED over and over and over again (even if, as a team, we were winning most of the time).
And THAT'S why I probably won't be playing too much with GAFfers.