Dps do tend to get the least comms but they do still get them quite often. So I'll usually try and reward one of them first. Keep in mind that a lot of players are lazy and probably don't think of tossing comms around.

Anywary my comm process is
1. Attitude
2. Competance
3. Appropriate role/race (roegadyn tank, lala mage, etc.) and Appearance

#3 being my tie breaker