There was a discussion on woodcentral a few weeks ago on this. But I have a Grex orbital. It takes a 2" or 3" pad and I have tried it a few times and it is just something I can't get used to. With a normal sander, like the Sioux, when you apply pressure, it spins and cuts harder. With the air, it will stop. It takes a very light touch, sort of like using an inertia sander (Vic Woods, Sorby, Tim Skilton), so it doesn't work well for heavy sanding, or even sanding when the lathe is stopped.
If there is an adjustment on this thing that I don't know about, that allows greater pressure, someone please tell me.