Well lets start with the basics. RPM is for a rotary buffer, and OPM is for an orbital machine. I am familar with the "Waxmaster" and its an orbital. It will be useful for removing wax and removing other products, but that is about it. They don't really have enough power to remove swirls or correct surface damage. If you just want something to remove the wax from your car, then it's fine for that use.