I have gone back and forth about once a week for the past year. The only Class D I have owned is my current NC1200 Acoustic Imagery Atsahs. I also own a McCormack DNA-2 LAE that received Steve's Signature Edition upgrades (the best) in 2014. Before that, solid state with Clayton Class A M300s and M200s, Lamm Hybrid M1.1s, and top SS amps from Cary, Herron, BAT, and McCormack (DNA-500).
It has been difficult to decide whether I like the McCormack or the Atsahs better and I am set up so I can easily switch between them, which has been interesting. From a purely sonic standpoint, the Clayton M300s were the best I have owned but the Atsahs and McCormack are close, and have ergonomic advantages over the Claytons. The McCormack and the Atsahs have slightly different sonic presentations but the differences are not large and both sound great. I would say the McCormack sounds a bit cleaner and more extended while the Atsahs have a touch more tonal density. Both have great bass and, again, the differences are small.