I use a multi master (250 with the quick blade change) at work and it is a nice tool. They are kidding them selves with the price of attachments. The blades, the paper, all of it a solid rip off. Of course it does a few jobs that can be very difficult any other way, and it excels at them. I don't find it to be an exceptional detail sander and do not use it on any fine work. Its more of a paint stripper in my mind than a precursor to a good clear finish.

I bought a Rockwell soni-crafter a few weeks ago for a side job installing some flooring and used it to under cut a dozen door jambs and remove 20SF of linoleum glued down with something I imagine was designed by SATAN. In any event, the sonicrafter is a solid tool worth considering if your in the market for an oscillating tool of this sort. My results were very similar to those with the Fein tool. Its built like a tank, but blade changes and angling not quite as convenient as the Fein quick change.

I checked out the dremel and found it to be too light weight and of dubious quality for commercial work. I hear the bosch has a short battery life under heavy use. I can tell you the multi master is the best, but the sonicrafter is a VERY close approximation and the accessories are priced much more reasonably. I had very good results with the blades in terms of life.