My experience with Class D amps demonstrated to me that the quality of the sound was completely based upon which amp I had used. One particular amp was nice, but it grated on me with extended listening time. It was just too bright on the upper frequencies with a harshness. I suspect it was the generic Class modules which were used in the amp; it was not a very expensive amp, and I'd say it was a perfect starter piece for kids in college who want a lot of output, very light weight and easy to move around and as I noted, affordable. I was comparing it against my A/AB amp at the time too which was my baseline.
I got a great deal on a pair of not very used Anthem Statement M1 Class D mono blocks, these are very expensive amps, but the price was great from the original owner who had a bad case of habitual upgrading syndrome. He just had to have the super expensive $30K class A monobloc amps, so he let me have the M1's at less than half cost. When I installed these amps (with dedicated 240V 15 amp each with direct runs to my service entrance), I was blown out of the park with what I heard vs. my A/AB fancy amp. I knew within 2 minutes of listening to some very familiar vinyl these were game changers. By the end of the weekend, I moved my A/AB amp out of the rack and put into a home theater application.
The Anthem M1's are very sophisticated design amps using internal liquid cooling heat pipes for the output devices and they use a proprietary feedback circuit which is makes them so amazingly smooth in the upper ranges vs. other Class D's I have heard. I also experimented with them on 120V input vs. 240V input and it's still very good, but the dynamics on 240V make it definitely worthy of using. Plus, they jump up to around 2300 watts output per amp for amazing headroom.
I will never sell these amps! It doesn't get much better than this as it's like being in a live venue.