Tweetnot to much difference. some guys seem to have more nerve problems. I just switched from 1 inch to 5/8 inch needles for my quads and I like it better. If you have a low bodyfat then I would use that. just make sure you massage it and apply heat after the shot to move that oil. other than that it is easier I think with quads because you can use both hands and you are not reaching around to find your ass.