I'll commend people I think deserve it regardless of class. The tank did real well managing their cool downs? Comm. The healer saved the party with quick thinking or kept another member with a constant desire to eat AOE's alive? Comm. A DPS player clearly knows their rotation and is putting everything they have into it? Instant comm. Though when it comes to DPS I'll also instantly comm any SMN/RDM that shares rez duties and or mana shifts me as the healers; and any aiming class that actually uses tactician/refresh/peloton gets it as well.