I've known Ralph for a while and have been an Atma-Sphere customer for some time owning an MP-3 preamp and M-60 OTLs. I have had the Class D amps in my system now for about 6 weeks. In the simplest of terms I will say they made the OTLs obsolete. On top of that I have lent them to 2 people and both of them placed an order after their listening comparisons.
I have Bel Canto REF1000 MkIIs and while I think they are a very good Class D amp, I prefer the Atma-Sphere. In my opinion they have all the attributes of a tube amp with the transparency and speed of an OTL, as well as no heat to deal with and they are much more power consumption friendly. In comparison to the LSA, the LSA came off grainy in the upper frequencies, it was clearly heard after listening to the Atma-Sphere amps.