Zack is a good guy, I ran into him at a conference years ago, where I was wearing my own mobile setup with a HUD and a Twiddler and we hit it off b/c we were both trying to solve the same problems, however his design was way better!

I'm glad to see this iteration, as it looks like it is getting closer and closer to reality. He is definitely on the cutting edge of these things in terms of usability.