We get good print results in general with the glass coasters from The Transfer Press - had a few when we first started doing them where the print seemed to stay underneath rather than go through the white printable surface- but only about 4 or 5 out of the 100s we've done. The one thing that we do have problems with though is the durability of the printed surface - it seems that it chips off a bit too easily, and a small chip or scratch in the surface is then very easily scratched to be an even bigger area. Obviously this is more of a problem when packing and storing them for sale, but I wouldn't be happy buying a set of coasters, and finding the artwork scratches off easily when I get home. Has anyone else seen this, and come up with a solution - we've been thinking along the lines of putting a coasting of clear varnish on them or something?