Doubt all you'd like. I've polished out plenty of wetsanding marks with my Griot's. In large and small sections and it didn't take a crazy amount of time to do. It is much faster with a rotary, but the flex isn't a rotary and neither is my Griot's. AGAIN, I say, if you have the money, GO WITH THE FLEX. If money is an issue, then the Griot's is a powerful alternative to the Flex. The forced rotation on the Flex is incredibly strong, but the power of the Griot's puts it right next to the Flex in terms of correction power. They both have their place and neither is better than the other in terms of correction ability. The flex appears to be easier to use and is more consistent than the flex due to the fact it keeps up it's rotations no matter what the circumstance is where the Griot's will have issues keeping rotations up based on the pressure you use and where it's applied on your pad.