I have played both at Winter NAMM 2011. The Glasstones does have a lot of sustain, but I could not get over the weird scratchy feel of the string sliding over the glass. Bends were not smooth feeling because of this (they sounded good though). Open and fretted string sustain was fantastic. Now, CrystalFrets did not have the nearly as much of that scratchy feel and the sustain was not as long lasting, whether open or fretted. However, Glasstones is a complete guitar and CrystalFrets is a modification to a fretboard. It really is silly to compare the two and I could care less about the patents. Just give me something that I like! Both have their own uniqueness, but I could take any of my guitars and have it Crystal fretted and cannot do that with Glasstones.