ORIGINAL: Geistware
I will have to agree, A one roll roller is probably the hardest maneuver to perfect. While most manuevers can be off but look like 10's, that maneuver will show that you are off in so many ways.
I'd say this about almost all rollers. It is the only figure I know of where you can actually zero and still have done something that looks like a roller to the untrained eye. I once gave a pilot a zero and he asked me why. I told him it was because I could not give him a minus 19, I had to stop at zero!!!