My wife and I have Oceanic Versa Pros (the navcon model). So far, we're been pretty pleased with them. I like the simplicity of the user interface (two button), and the size and appearance of the computer face itself.
The only issue we have with the computer is that the clear plastic protector over the computer face tended to trap bubbles on our last dive (in 94 degree silty water). This necessitated shaking the computer around a bit, but once the bubbles were dislodged, all was OK.
Has all the features we were looking for (including Nitrox) - about the only thing it was missing was air integration. If you're interested in it, theres a pretty cool demo on their web page (
http://www.oceanicworldwide.com) that mimics the operation of the computer - this is what really sold me on it.
As far as software goes, I just received a copy (been waiting for the software to be released ever since I bought the computer about 6 months ago). Unfortunately, the installation process totally trashed my Windows NT machine (which the software claims to support). Tech support will be receiving a nasty call on Monday.
The software CD itself contained versions of the software (called OceanLog) for many of their other computers as well - not sure if there are any major differences per model of computer. The data cable plugs into the side of the computer, so you don't have to remove it from the boot to transfer data.
All in all, we've been really happy with them.