Don't rush them into the mid of the frontline since they will get focused and bleed you all the time. Same goes for every elite infantry in the game (and also flamethrowers).
use them as defensive or on the flanks to fight in 1v1.
also, with units that have smoke nades, they are usually better than trying to use frag nades, throw smoke to cover the gap between you and the enemy so you don't take unnecessary damage
