I just did the newbie mix this evening and I had a great time. I'd had some experience in the pug irc (pug.na and tf2mix) and it was meh... But I did 3 newbie mix matches and they were excellent. I main scout, and I actually feel like I got some synergy with my scoutbro and (to a small extent) my roamer. It was very rewarding. Thanks to the people who make newbie mixes happen, especially the coaches!