I have not had a Class D amp that bettered my best Class A or even AB amp yet. I have kept it under $3K for the various Class D amps I have tried.
That is interesting. I wonder how the AGD or the Atmasphere amps compare to some Class AB amps that are highly rated in the <$10k range. But I have also read reviews, where owners were happy with the GaN amps and had no remorse replacing the AB. Of course, everyone's experience is different.