Corian is softer, and it works real easily. The Tusq stuff, which I believe is silica-filled Delrin, is so slippery that metal files tend to just slide around until you put on a bunch of pressure, and then it cuts really quick. I find that whole Delrin family easier to work with abrasive wet/dry paper, or diamond or tungsten carbide types of tools. I'm happy with bones, I just keep several blanks around all the time.
As far as sound goes, I've never done any kind of accurate double-blind study with identical guitars or such (NObody ever does those things, they just rave about whatever they bought last). :icon_biggrin: :toothy12: :icon_biggrin:. I can't possibly image there's more difference in tone than you'd get from moving an amp's knobs from "3" to "3 1/2" or something. The delrin/Tusq stuff probably is a bit better about staying in tune with a whammy or bends, but once you learn how to cut a good nut, the bone works fine at that too.