Been shooting steel plates and poppers for some years. As long as they are made of suitable steel for the calibers used and the users are looking at the surface for possible dents on the steel, the amount of bruises and bloody spots are low...
Atleast with handgun calibers the majority of the bullet particles seem to disintegrate sideways from the plate, not so much toward the shooter.
Good example of shooting a plate with a rough surface is a 7.62x39 to the forehead from quite a ways back, wasnt me.