AS in this case is the Atma-Sphere class D monos which I personally found to be significantly better than the other amps I mentioned in those characteristics. I’ll try to be bit more specific:
I initially liked (after it was broken in) the NAD M22 as it was dynamic and powerful and reasonably resolving. But I also found it to not be tonally “dense”. I don’t mean lacking in bass, but perhaps this is what the reviewers call “tone color”.
For the PS Audio S300, I found it again detailed enough but also somewhat bleached tonally. That said, I also thought it quite good for the price - vastly better than the a Parasound A23 I also had laying around which I found to be lacking in resolution and overaly thick in the mid bass.
I had high hopes for the M33 Eigentakt. It was certainly smooth but it never sounded quite right to me and somehow music lost its energy. To be fair, that unit was also a preamp, streamer and DAC so it’s entirely possible one of those other functions was at fault. I never did try the T+A amps which are based on the Eignentakt module. Rumor has it those are quite good. But the rumors and reviews of the M33 were quite good too and I found it disappointing. For me. Others will clearly disagree.
The Atma-Spphere (AS) Class D amps I have found to be thoroughly enjoyable and satisfying to listen to. Tonally rich, smooth, powerful. Are there better? I’m sure. But I’ve also directly compared and found them fully competitive in my system to the Simaudio North 761 which I also own. I personally think the North 761 is in the top tier of amps in the $15-$20k range.
Full disclaimer: I’ve listened to a fair anmount of equipment to have certain tastes and biases. There are amps from a certain well known and regarded (even beloved) company whose sound I do not like though I’ve listened many times. The North and AS amps are what I like. As in all things, YMMV.

