I have both the T+A 200 and Mola Mola Tambaqui.
I'm still early in my evaluation of the T+A 200, but I can say without question it's bass presentation is quite substantial. I had to dial down my sub's by about 10% to quell the overwhelming boomy sound. I'll be honest I feel the MMT handles low frequency better then the 200, but I might possibly give the 200 the edge as far as far lateral left to right sound field width. When I say this I do mean very isolated far left to far right sounds appear to be coming from Beyond the speaker more so with the 200 then my MMT. However it's not even a question as far as holographics and center image generation the MMT is much more enjoyable in that regard than the 200.
The MMT is 3-5k more expensive then the 200 and to that I say the 200 is a great DAC, and it can handle DSD which is a draw especially with my SACD's.
I was interested in the 501, because of the DSP capability, but I was also very interested in the Meitner DAC MA3.
Now the MA3 and 501 being the roughly the same price I would definitely want to see these DAC's side by side to A/B them, but as interested as I am in these two DAC's, I am not interested in spending another $2,500 above what the 200 has to offer.