As a resin artist I spend an inordinate amount of time hand sanding. I am always looking for ways to cut down my sanding time. The Wolf Sander $179 is the work horse of my dreams. It has specialized belts that you can use with plastic and resin which do not scratch the surface. It will take the finish down to a 400 microfiber sanding grit, cutting in half my original hand sanding time. It also is great for sanding fine/sterling silver again with few scratches on the material.
Here is the link for the specialized sanding belts: http://www.ottofrei.com/store/search.php?mode=search and here is the link for the sander http://www.ottofrei.com/store/product.php?productid=16863&cat=0&page=2.