The way I understand it:
makita BO6040 - 2 modes:
random orbital (jiggle only, like porter cable)
random orbital with forced rotation (jiggle + spin [like a porter cable and a rotary combined])
flex - 1 mode:
random orbital with forced rotation (jiggle + spin)
Do I understand that correctly?
The porter cable and UDM type machines do spin as well as orbit, but the spinning is on a free-wheeling bearing and is a side-effect of the orbital motion - the spinning will be slowed, and can be stopped if you apply enough pressure to the surface. The flex, and makita in forced rotation mode, will always spin while orbiting as a forced action.. right?
The specs I found report the forced rotation of the Flex at 480 RPM max, and the Makita at 670 RPM, slower than a true rotary. Safer though!
Orbits per minute are comparable to the PC-style for both machines.
FYI - when reading a review of the Flex on properautocare, Terry says "The "throw" or amount of "jiggle" is not disclosed by Porter Cable but it is very, very small [blah blah] ...[The flex] oscillation also has a exceptionally "long throw" of 8 mm."
FWIW, On the Meguiar's forums they have a chart that compared the porter cable, meguiar's versions, and the UDM - and they are all reported as having an 8mm stroke there.