I am guessing the you are talking about the Flex 3401 Flex XC 3401, FLEX Orbital Polisher,flex XC 3401 VRG dual-action polisher,flex XC3401VRG,Dual Action polisher,FLEX buffer
The Dewalt sound like a rotary polisher, where the head just spins in a circle.
The Flex 3401 also has a spinning head, but also has a random orbital rotation, which mimics the motion you do when polishing by hand. The Porter Cable 7424XP (and variations) also have the random orbital motion. The Flex 3401 also adds a forced rotation to the head, so it is kind of in between the PC and the rotary.
I am sure Mike Phillips has a post on here with nice visuals so you can see the motions I described.