The only difference I'm aware of is the 1996 model is supposed to have 2 piece key tops and the '93 has the one piece key tops. I didn't break the seal on the 1996 so I can only tell you what I saw on clicky's site before I ordered it. I guess I'll keep it sealed until I really need it.
I'm using the '93 now on my main system. Typing is now an event!
My wife came into my office and noticed something was different. She said oh you went back to the old keyboard? I said no, this is one of the new ones I just got. She said what? It looks old...
I said yeah, isn't it beautiful?