I was more curious about the differences, good and bad between class A and D. Assuming that we are talking about amps that were designed for the best performance at their price range, it is a closer race to me about which I prefer. In fact, it matters as well about the amp matching the system to begin with, as I am finding out. In the best combinations that I have to offer in my system, each seems to hold its own. There may have been little competition years ago, but the gap is quickly narrowing. It makes me envy those who have the opportunity to own multiple systems.
FWIW, I just built a class D amp designed by Pete Millet, as well as another type of class D amp designed by Peter Nelson IIRC. Each of them sound different. And different sounding still is my class A amp designed and built by John Dee, formerly from Sudgen Audio. I just feel fortunate to have had the experience.