I favor the DPS in general. Not that I don't appreciate a good/standout healer or tank, but even while commendations are overall meaningless, the "You have received a player commendation!" can be uplifting.

I play BLM a lot these days, and while I received a ton in SB as a healer, it never felt as good to get them as it does now. Of course, you'll never know the reasons WHY they commended you in particular... But small pleasures, I suppose.

Otherwise, uh... I tend to favor people who simply talk more than duty-start greetings. Even if chatting in the middle of fighting is not really possible, it leaves far more of a mark if a conversation is had.