Theta Data Transports

I have heard that older Theta transports are still quite decent by today's standards and I'm thinking of maybe picking one up to see if it provides a significant sonic improvement over the CDP I'm currently using as a transport. In researching older Theta transports, I have seen mentions of the following transports:

Theta Data II
Theta Data Basic II
Theta Data III
Theta Data Basic III

I'm a bit confused about how each transport differs from the other. Can anyone explain the differences between these Theta transports? Has one or more of these units proven itself to be better than the others in terms of sound, reliability, etc.?

Basically, I'm trying to determine which would be the best transport to try in the $400-$600 (used) range. Are there any other transports besides the older Thetas that I should be looking at?

The Data II spins CDs and LP-sized laserdiscs. The Data Basic II spins CDs only. I'm not familiar with the Data III. There is no such thing as a Data Basic III; the Pro Basic III is a DAC, not a transport. Last year my nine year old Data Basic II required a trip to the factory for a lube job and to replace some capacitors. Figure on a few hundred to factory fix yours if it breaks. Nothing lasts forever. For $500, Proceed transports are worth a look but I heard the factory went under a while back. Nowadays, few companies are making CD-only transports.
The DATA III sounds the best it plays laserdiscs and CD's has a separate door for the CD drive also.
You might want to check some past archives regarding reliability issues as far as the Data Basic's mechanism is concerned.

When I was considering a Theta transport three years ago, I stumbled on threads regarding this. I think it used a discontinued Philips mechanism and Ed Deitemeier of Theta told me they were having a difficult time finding replacements for it. I opted for the Pearl instead because it used the Pioneer Stable Platter and that mechanism was still in production at that time. However, I think it too has since been discontinued.

If in doubt contact Theta, and if Ed is still with them, he is a very helpful person and should be able to answer all your questions.

Good luck!
I bought a Data II laserdisc/CD player a couple years ago. Unfortunately it was damaged in shipment. When I removed the cover, I was astounded to see how poorly this unit was manufactured and assembled. It looked like a product from a startup campany run out of a garage! This was not at all what I expected from a company that got rave reviews over and over. I have no doubt their products are much improved by now, but I would be very cautious with the older transports.