I added a photo page of Resin Castings to the PHOTO ARCHIVES.  I’ve been spin casting resin for more than 20 years. When painted, the resin castings are indistinguishable from the metal versions.  The problem with spin casting resin is that the labor costs are pretty much the same as casting in pewter.  Additionally, the material savings are not realized when you consider the resin sprues have to be discarded where metal can be re-melted.