I've had an Oceanic VT Pro for almost two years, and I'm quite happy with it for recreational diving. The display is large and friendly, it is very easy to program and use, and wearing it as a wrist unit out of the water makes for some dead-sexy accessorising, along the lines of we geeks that wore calculator watches years after they had gone out of style... ;0)
Drawbacks that I've discovered over time are:
SOFTWARE:
Oceanic's software is only written for Microsoft operating systems, and they won't provide the docs for the communication between the PC and the DC so that a person could retrieve dive data when using some other (read as: more reliable, secure, etc.) operating system. One can fairly easily get the software to run in a Windows emulator under Unix/Linux, but then can you really trust the data?
Also, the DC will not save/download actual tank pressures for the dive, instead giving the (IMHO) useless Air Time Remaining. I think that this is a useless metric since unless you know your breathing rate for that particular moment, you can't figure out how much tank pressure you had at that time, and the VT Pro doesn't ever display your breathing rate. I am one who would like to be able to point at the dive profile and say, "Ah, here at this point, where I had 1800 psi, is when I had to hide from the manatees". As it stands, you have to know how many minutes into a dive you did everything, which I am not prone to noticing since I dive to lose track of time, and my governing limit is how much tank pressure I have remaining.
The database the program uses is prone to corruption, and I lost my first 60 dives because the DC went bad and uploaded dirty data. Attempts to manualy recover the data were fruitless, and basically defeated the whole reason for downloading and saving my dives in the first place. A simple one-table flat file would be sufficient for storing the dive sample points, IMHO, but the database is much more complex than I feel it needs to be.
WIRELESS:
I'm not sure what the cause of the trouble was, but I replaced the batteries using the same type/model and according to the instructions, and the unit worked well for a week or so. I took it to Florida, and on the first dive on the Eagle off of Key Largo, the 1st stage transmitter cut out at 120 feet. I'd looked only a minute before and knew that I had 2000 PSI, but when the link wasn't re-established after 2 minutes, I had to abort the dive. The unit was usable afterward, but was extremely finicky about synching with the 1st stage ever after.
To Oceanic's credit, a simple stop by the LDS and one phone call later, they replaced the whole DC for free. Also, Oceanic isn't the one that makes this computer and I am sure that they didn't write the PC software for it, either. This computer serves my needs very well, and I'll keep it until I upgrade to a Cochran of some type.