Got 13/17 at the moment, shame it as far as I know does nothing once you've got them all
The ones I've got left aren't too hard :
Head of the Class - Play a complete round with every class
Team Doctor - Accumulate 25000 heal points as a Medic.
With Friends Like these - Play on a team of 8 made up of only players from your friends list.
Lightning Offense - Win Well in 5 minutes or less.
Ironically I've done the first and last of these and they didn't seem to get acknowledged.
My favourite stat so far is:
Longest life - 35:04 (as Engineer)