This can be a tough one to answer because what's best for me may not necessarily the best for you.
There are three machines that come to mind;
- Flex 3401
- Griots 6"
- Porter Cable 7424HP
Theses seem to be the most popular here rise to the top of the list. I personally own the Flex 3401
and the Porter Cable 7424
My Polishers from the left; Porter Cable 7424, Makita 9227, Flex 3401, and the Flex PE 14-2-150 The Flex 3401
The Flex 3401 is the most powerful dual action polisher that I'm aware of. It's power combined with the forced or gear driven pad rotation allow the operator to really concentrate of the downward presser needed for efficient correction. Flex XC 3401, FLEX Orbital Polisher,flex XC 3401 VRG dual-action polisher,flex XC3401VRG,Dual Action polisher,FLEX buffer Griots 6"
The Griots 6" dual action polisher boasts being the most powerful of this style polisher on the market. The Griot's polisher also boasts more torque, which keeps the pad moving even under pressure. Commonly the pad will stop rotating on a typical DA polisher when pressure is applied. Griot's Garage 6 inch Random Orbital Polisher is designed to keep moving so imperfections are eliminated faster. Griot's Garage 6 inch Random Orbital Polisher, Dual action buffer, DA polisher Porter Cable 7424HP
The Porter Cable 7424HP is in the same class as the Griots polisher above. Although not as powerful according to the numbers, it outsells all the other brand of this style polisher. Could it be the name Porter Cable that drives sales? Quite possibly but the same Porter Cable is also synonymous with quality and performance.