You seem to be drawing a lot of conclusions about the Purifi module from the absolute cheapest implementation. There are many Purifi implementations that have a much better power supply and much better input buffer that are admittedly more expensive, but then so are the amps you are comparing.
I have been pretty impressed with the Purifi modules in my own DIY amp. It doesn't quite match my Pass XA60.8s but holds it's own very well with less expensive class A/B amps including the Parasound JC5 that I owned for a while.
I haven't directly compared my Purifi amps to the other amps you have, but I used to own the ML 333 and I think a good Purifi implementation could easily give it a run for it's money, and would likely surpass it in many areas (IMHO). Of course, it all depends on system synergy.
I have been pretty impressed with the Purifi modules in my own DIY amp. It doesn't quite match my Pass XA60.8s but holds it's own very well with less expensive class A/B amps including the Parasound JC5 that I owned for a while.
I haven't directly compared my Purifi amps to the other amps you have, but I used to own the ML 333 and I think a good Purifi implementation could easily give it a run for it's money, and would likely surpass it in many areas (IMHO). Of course, it all depends on system synergy.