Santa (dressed as the post man) brought me a new Vytec this Christmas. I'm upgrading from a non-nitrox Oceanic Prodigy, which I'm in the process of selling. I gotta say, this is one cool computer. I didn't get the AI transmitter though.
With this computer, you can purchase an interface from a third party - Athens Home solutions
http://www.athenshomesolutions.com/
for about $50 + shipping (hopefully mine will come today) and then get a free download of divemanager from the Sunnto site and you'll be able to transfer your dive profile over from the Vytec to the PC and analyze it after a dive. Pretty neat stuff.
From what I've read in the manual, the Vytec allows three nitrox mixes, along with an air and guage mode. I'm still playing around with it so I'm not sure what else it does.