Okay, let me ask a question or two about how ROS's are supposed to work in general, 'cause I've never used one before, and don't know quite what to expect.

When we're talking about RPM's, what does that mean? Does that mean that if I put a mark on the edge of the pad, I should see that mark go zinging by that many times per minute, or is it really just a measure of the motor's speed inside the sander?

When I turn my new sander on, the pad has about a quarter inch or so of (random?) jiggling movement, but looking at the holes in the pad, I can see that actual rotation of the pad is very slow. If I mark the side of the pad, I'll only see that mark go by about twice a minute.

Now, again regarding my specific problem with the sander, it sounded from the ad copy that the thing is supposed to slow way down when it's not in contact with a work surface. (from Amazon.com: "An easy thumb wheel controls the speed, which ranges from 5,000 to 12,000 orbits per minute. It's quiet and easy to handle. These features alone make it a great choice, but here's the smartest thing Porter-Cable did with this little gem: a pad brake will immediately slow the revolutions to 400 per minute when the unit is lifted off the work surface. This helps prevent gauging when you lift the sander off or place it back on the work surface.") I am not seeing that at all. The unit runs at the same speed regardless of whether it's against a work surface or not. I called Porter Cable customer service, but it wasn't a productive call. I don't think I was making any sense to them. (Maybe some of you can relate!) I'm thinking I'll go back to Home Depot and ask for a demo of the unit, to see how theirs works.