On a neglected car a properly trained detailing technician (hahah my title from now on Brian! j/k) with a rotary will beat the PC anyday.
Yhe PC is a good polisher, will make good finishes great, but he PC has its disadvantage, it has a random orbit motion. This translates into less power and heat which will not give the technician flexibility in paint correction (evert ake a dull knife and put it trhough butter, thats the PC, now take a hot one and put it through butter, thats the rotary.) The rotary has lots of power though (PC is 3.7 amps while Makita is roughly 8 or so?) it will generate heat quickly if you dont move around quick enough or if you use the wrong pads/compounds it will create more swirls.
The rotary will turn a very neglected finish into a near flawless one though. A 1996 Honda Accord that was NEVER waxed in its life after delivery was done with the rotary yesterday (2X Automotive International's Liquid Paint Correction Cream (like 3M Perfect It II Medium cut rubbing compound) with rotary and foam polishing pad, 1X foam pad machine glaze with rotary and foam finishing pad, topped off with
Meguiars #26 with foam finishing pad and PC.) The results the surface felt like 150/220 grit sand paper after a wash. After the rotary compounding/polishing the surface was 95% perfect, some marks were too deep to polish out (primer) but other than that the surface was 100000X better than before, we didn't have time to clay it (ok we didn't have the energy) but the surface felt close to a clay job, wasn't as smooth as glass but DARN near close. The owner of the car was VERY happy with the resulting finish. I wish I could of taken some before and afters but I didn't have time (we had 3 cars to do in about 10 hours.) Next time we will have some before and afters.
So to make an analogy, PC = Glock 9 mm, Rotary = CAR-15 assault rifle. The PC has its everyday use for average to good cars, but the rotary will be needed to make the neglected finishes as close to showroom condition as possible.
Jason