I was looking at the Suunto Vytec DS and the Oceanic VT3 for my computer. I had heard many good things about both from very reliable sources. I decided to go with the Vytec because many of the people I was diving with had one, so I could get help with usability easy. I have had a few synchronization problems, but overall it is a good computer with 3 gas blends available. All 3 can be 21-100% O2. I would say that the D9 appears to be basically the same computer in a smaller factor, and with a digital compass built in.
I don't know anything about the Uwatec Smart Tec, but I've also heard good things about Uwatec's products.
No matter which way you go, if your going AI, I would suggest also to get a backup SPG. That way, you don't HAVE to abort the dive if there is any transmitter issues. You can get a small (2 in.) SPG and mount it almost anywhere out of the way. I have mine on a 22" hose clipped off to a hip D-ring. I only check it about once a dive, just to make sure I can reach if it's needed and to double check my AI.
Hope this helps some.
-Sean