The clear stuff is a different brand of thermoplastic called Holstex, but it's basically the same as Kydex. Just brand names. I've heard the Holstex is supposed to be "more formable," or something like that, but I haven't noticed hardly any difference. The Holstex seems a little more prone to chipping around the egde, but I only say that because I bought b-stock that came with some chipped edges, I haven't experienced any chipping myself. So it seems to be as durable as the Kydex.
Kydex also comes in all sorts of colors and patterns, as I'm sure Holstex and the other plastics do. I personally like the black for my stuff, with little exception, but if you'd like me to do any custom sheath work, the color choice is all you. They make Kryptek camo Kydex, which I've been meaning to get for a while. That stuff looks cool.
Shoot me an email through the forum if you're interested!
Great thanks. Still debating what my first kukri should be. But I will definitely be interested in a molded sheath for it. I'm not into camo or black really.