X2 on the 4" grinders. A friend of mine had one that needed new brushes every other time he used it I think. Why else would it come with an extra set of brushes
Stay away from 1/2" power drills if you want to use them like a real drill. A helper of mine tried mixing thin set mortar for a tile job we were doing and he burned it up the second time he used it. I warned him, but he tried...