I have both and chose the Flex over the Makita (actually sold it right after I got my Flex). Both are well built, metal bodies. The Makita is smaller in size but feels a little heavier. Flex is more ergonomically shaped and gives a better feel, as well as better control than the Makita. The trigger vs switch is a big factor. When comparing forced rotation apples to apples, the Makita jumps alot more than the Flex, making the Makita a little harder to control when compared to the Flex. Very similar correction ability, but would probably give the edge to the Flex.
The only thing the Makita has over the Flex is the RO mode, which makes it very easy to apply sealants and waxes. The RO mode may also be good for beginners, but the trigger on the Flex will compensate for that.
Both have proprietary backing plates and permanent power cords (unlike the Festool, which is removable).
Design-wise, I'd say the Makita is closer to a porter cable/UDM shape, Flex is a cross between a Metabo (knobby head/handle) and a Makita 9227 (trigger).
Sorry if my review was poorly written, its 11pm and I've had a few "sips" of beer at a dinner function tonight. I can clarify any questions in the morning.
