Grenades work pretty well. But you need be clser then the max range. It you toss at max range theres like a 75% chance the grenade will fall in front of the cover blocking some of the blast.. or its what I have noticed also. If you throw it farther then cover, then 1/2 the time they pull back on to the grenade dealng more dmg then if they sat still.
Dont give up on grenades yet
