I've used both, but I can say that there really is no comparison between the 2.

First, step up to a 6" that will instantly make you sand faster...after that it's like driving a toyota vs a Mercedes. Yes they both work, (really it's the paper that does most of the work) but how does it feel....how consistent is it etc. I use a Festool and have no intentions of going backwards (unless another great product comes along) it's not cheap but it does the job great. And PLEASE don't discount dust extraction. You really should try to capture as much as possible, even if you're working outdoors or on jobsites....not only will your sanding consistency improve but your health will potentially benefit. You can't see the stuff that hurts, and even the Festool or Mirka products out there don't get everything they just get more. Even if going into the little bag instead of an extractor. Also, don't bother buying it for that reason and then using a $50 shop vac with regular filter....it's still going to send most of the harmful stuff out. Doesn't mean you have to buy a fancy one (although there are great models out there) but at least buy a hepa filter for the one you have. Good luck.