Would you mind elaborating a little? Because I read ASR's review of the 2220 and it looks similar to this Nad to me? Even where the Nad measures better, is that even audible?
Over 80db improvement in Signal to noise ratio, will definitely be audible. This is especially true as the number of channels rise.
At the moment these units are far too expensive for most to consider using in multichannel AV systems. At the moment development costs are being paid off.
In the long run these amps should be much cheaper to produce. Even better they waste less power and don't make much heat. So we will progress to active speakers being the rule. Passive crossovers waste at least 50% of the amp power in most passive speakers. In addition, passive crossovers are highly limited in what you can achieve, for one thing you can only cut and not boost power. So if you have a dip in response, you can only cut either side and waste more power. They are also awash in time smear. The components are bulky and expensive if you use high quality low resistance inductors and avoid electrolytic caps.
The real "pay dirt" from these class D amps, will be much improved speakers, and those differences will be highly obvious and glaring. Speaker deficiencies are so prevalent, it makes even significant improvements in power amps inaudible.
We will see the death of the stand alone power amp, it will come eventually.