USD vs conventionals really boil down to what terrain you're riding, and how particular you are. A preference thing, if you will. Those that want 'em know what they want and will buy them. Nice looking design, btw.
FWIW, Gary Emig has been making these conversion clamps for a while, they seem to sell well, and they're still in production. The 650L, 600R & 400R can do the same swap with a steering stem change.
So if you dig a Scott's damper, another cool option for a neat swap.