I've never played with either knife, but they're so different that I don't think that they can really be compared w/ each other. It really depends upon what you're looking for in a knife. In so far as the metal goes, I've heared mixed reviews of San Mai III, most not in favor of it. As I've never toyed with it, this is only hearsay, but I hear it's overblown and not worth the extra $$$. It sounds like Carbon-V is the way to go.
PS. If I had my choice, I'd get the Tanto, sell it, buy the Trailmaster and either pocket the extra cash or buy another knife w/ it.