mike,
I don't believe the end result will be any different; however, in my experience it is much easier to put down a thin layer of just about any product with a PC, and in the end, I generally use less vs. hand application. Assuming you already have the PC and pads, give it a try sometime . . . I think you'll find the added speed and convenience worth it (especially if you apply your sealant by machine, too). You'll find that the first panel or two will require more wax/sealant on the pad than you're used to for hand application, but once the pad is primed, it takes only tiny amounts for subsequent panels.
FWIW, I've found the Sonus SFX-3 pads to absorb *very* little sealant/wax. Liquids don't penetrate into the foam very far, so most of it is given back to the paint instead of being sucked into the pad and wasted. If you really want to be stingy on how much sealant you use, the 4" SFX-3 spot pads are great. The smaller pad wastes very little product, and they're small enough to get into most spots.
Tort