Hi, Lildiver,
I've had an Oceanic Data Plus for 3 years,and I like it very much.It is easy to use,comes with a great set of instructions, and has served me well in diving with air and nitrox. The Nitrox range is 21 to 50 %, and must be set before each nitrox dive. If you dive air only, there is no need to reset. You can dive air and nitrox on successive dives by treating the air dives as a "Nitrox 21" dive. It has a 2 graphic displays (Green-Yellow -Red Zones), one for nitrogen loading and another for O2 exposure, as well as the usual depth, dive time ,max depth, NDL time remaining, and a color coded ascent rate sysyem. It has a single button for activation and for the backlighting (u/w). Pushing the button will also display the temp.
As far as the Data Plus 2, it has 2 buttons,which I understand allows the user to access more options, but I am not sure what they are. I think it replaced the Data Plus, although I have seen both available. By the way neither is air integrated.
From feedback on dive boats, Oceanic Computers seem to be very reliable and user friendly, although last month in Cozumel, I met a couple who had Oceanic Air-integrated Computers (Model??) , and No real idea as to how to access some of the info, or what the numbers on some screens indicated. If the Manuals accompanying all oceanic Computers are as clear as the Data Plus Manual, then I believe that encounter was a case of "user error'.
Good luck with whatever you choose.
Miked