Theta Jade or Basic II

Both are very similar - excellent base, dynamics, transparency, detail and cost far less than other transports at their performance point. The Jade is, to me, a little better...probably because it puts out less jitter and it's a later generation design. Also, there are instances of mechanical issues with the Basic's drawer assembly and laser tracking system. Overall, I would go with the Jade hands down.
If you really want to get the best out of the Gen Va and are not willing to go in the Levinson 31.5 altitudes, the Levinson 37 or the CEC TL-1 will give you exceptional performance and out-perform the Basic and Jade. I have a TL-1 on my Gen Va.

I run a Pearl with my DSPro Basic IIIa. The Jade is similar but more sophisticated. They both use the well regarded Pioneer Stable Platter mechanism (the little turntable platter that the disk rests on with the data side facing up), but doesn't your Miles as well? The Jade goes a step further than other Theta CD transports by employing a digital buffer circuit at its output to lower jitter levels going into the DAC. I think my Pearl sounds great, certainly better than the players I was previously using as transports (none of which was as good as your Miles), but I've never heard the Jade, and its been so long since I've heard a Basic II I couldn't make a comparision. I send the signal from the Pearl through a Monarchy DIP for jitter reduction, which I like the results from, but the Jade may not require that. The Jade should in theory sound the best, but it also seems to go for around double what many Basics are listed at. The possibility exists, however, that the Basic might not even be as good as the Miles you already have. Use the balanced AES/EBU connection on XLR for best sound, if you don't already.

I owned both and always thought that the Data Basic II was the better of the two units. I thought the bass was better with the II than the Jade. I always regreted selling the II for the Jade. The Basic II was just more musical. Good luck.

I use the Basic II with the Gen Va balanced. My brother bought a Jade and we compared the two at my house and his. He immediately sold the Jade. 'Nuff said.

Interesting stuff about the Basic II. I do remember Martin Colloms' original Stereophile review of the Jade did mention the possibility of some advantages he ascribed to the older Basic II in bass and dynamics, but overall I think he preferred the newer unit, mostly for its smoother and more resolving presentation as I recall. When I was trying to decide whether to get a Pearl or a Basic II used, I spoke more than once to Ed at Theta, who is a very helpful and forthcoming guy. With nothing on the line for him or the company (both units were already out of production, as were all of Theta's CD-only products, the company having moved to DVD-based transports exclusively), he liked the Pearl a little better and thought it was worth the extra money used (a smaller increment than with the Jade), but I think part of that recommendation was derived from the difficulty in repairing the older discontinued Philips drive mechanisms in the II. Since the Stable Platter mechanism has now also been discontinued from Pioneer, that point may well be moot. I have seen some past posts criticizing the S.P. mechanism for its plastic supporting structure vs. the Philips' metal, but I don't know that this translates directly into a potential sonic advantage (the plastic used on the S.P. is very heavy and reinforced with molded-in cross-strut construction). However, I do believe it is true (somebody correct me if I am wrong) that the Basic II originally retailed for more than the Pearl that replaced it (though not as much as the Jade?), for whatever that's worth. Elgordo, care to elaborate on your comments with more specificity, rather than just saying "'Nuff"?

 I've been looking at older Theta transports, too. Has anyone compared these to the newer models used just as transports?  While common sense would seem to say that something purely focused on CD would be better, I read somewhere a very good review of the DaVid, and then the Compli of course was SACD. Have people compared those to these?