Mark Levinson 36 dac or Theta Gen V Best?

I don't know all the Pioneer stuff. But based on the Elite multiformat players that I've heard in showrooms, I think a good minimimalist 2ch DAC from a manufacturer other than the consumer giants, should get RBCD close to the level of SACD or DVD-A on the Pioneer. IMO the older ML stuff sounds sterile. The Gen Va is a better choice, but has a slightly synthetic mid/treble region by comparison to more recent top units.

So,what kind of DAC should I be looking at?

Based entirely on readings, of used ones on Audiogon now $1-$2k, two Altmann Attractions optioned with Jisco jitter reduction, or perhaps an Audio Note 2.1. Check out the Positive Feedback review on Altmann vs. AN. For Altmann you will need a fast 12V battery like Optima Yellow or Red Top. If cost no object perhaps Empirical Audio.

I've owned both. I was a theta fan for many years, but when I tried the Levinson No.36, it was a game changer. That good.

I have owned ML No.36 + ML Transport. I have also owned
Theta Va DAc + Theta Transport. I have tried various Transports with either, both never sounded as good as with
their respected Transports. I have found that Pioneer
DV-58AV as a nice rounded Universal that can do a decent
High Rez. DVD-Audio, a decent 2 Channel SACD, a decent
Redbook CD, a decent CD Digital Out to an external DAC,
even a decent Analog out on High Rez. DVD-Audio Multi-Channel, even decent 2-channel Downmix of the same. Picked a display model up dirt cheap for $100.00!