Yes Rob, I agree with you that most, if not all people like some for of harmonic distortion as it's hard/impossible to get away from it in designs terms. The THD levels maybe extremely low on all modern equipment BUT something other than THD modifies the overall balance of the equipment which is why most/all pieces of gear sound so different to others.
This DEQ test has shown that you can hear differences in the modded DEQ. The changes Tenson has made will add or subtract something in the signal, it's impossible for it not to. But as well as that the fact that the signal has to be decoded and then encoded MUST also do something to the signal. It's whether you like the outcome that matters.
Interestingly sample Y has been picked out by everyone so far.
I did my bit and listened to the samples and could definitely hear differences. Which ones I preferred is a different matter because to be honest I didn't like any of the samples - audio reproduction wise.
All samples run through a RME interface into my system.