We just cleaned a big church today with the cimex and orbot. I think that the orbital was quick, efficient and effective. I used the cotton pads and the sprayborg and just walked. Turned out great. The cimex is just THE commercial carpet cleaning system you need to have. Its fast, EASY and profitable.
But, if i were choosing between both... I would buy the orbital only because you can also use it on residential- more versatile. We use it for hardwood floors, tile, and more.
My 2 cents.