I am captain 1, thus the Quads are leveled to captain, the dual heavies are Lt. Commander, and deal more damage, and not that significantly less DPS.
As for Khemaraa_Iron_Hand_KBF look at the Damage to DPS of the Quads and the Damage to DPS of the Duals. The differences speak for themselves. The Dual Heavies, as you say, have their cake and eat it too, the Quads, do neither.