Mapman, Initially upon listening and buying a couple of the class D amps I found that they did most things overall to acceptable levels and felt their performance in most cases was overall quite satisfying.
However, in my case, I found that they felt thinner (not necessarily thin, just thinner) in sound than what I like. Maybe I am using the wrong term here so I will try to explain it better. My experience over time was that it seemed like the sound wasn't as full (not flat, bloated, or overly warm sounding), just not as impactful or with as much weight behind it. I also found that the sound staging, while being wide enough, always seemed to lack the depth I was looking for and also that the focus was not always consistant. It seemed to me to change with volume levels in terms of the focus aspect. I also found that as the music became much more complex, that the focus and soundstage did not hold up as it did with more moderate "sized" recordings. Again, these are parameters that are important to me for my own satisfaction, not necessarily what is either "right" or what others may be seeking (hence my recommendation to audition for extended periods of time). Additionally, as I indicated, I certainly have a limited experience versus everything that is out there and have not auditioned some of the super high priced D amps.
My other equipment that was in/out of the system included the following:
Amps: Krell FPB 200, M. Levinson 331.5, BAT VK-60 X 2 running in Mono
Preamps: BAT 30i (?), Cary SLP (?), J Rowland Capri (I really liked this preamp), Aesthetix Calypso
Speakers: VS4jr, Watt/Puppy 5.1, Wilson Duettes, Thiel 2.2 (ebay buy for $200 that I couldn't pass up, a great deal for those speakers)
Sources: Resolution Audio Opus 21 w/ GNSC mods (good player at a good price), EMM Labs, Esoteric X-03se
So you can see that the sound that I like is more on the highly resolving level (except as referenced via the BAT and Cary stuff - which didn't last that long by the way in my system for my tastes).
So I certainly don't claim to be an expert on Class D amps and while I have listened to several, certainly not to all by a long shot. My experience has been and continues to be for my sound type, I have found that components that have the biggest and best power supplies have delivered the most satisfying results for ME. Not to say other should or will have the same goals as I.
However, this experience is the premise for my recommendation for long listening sessions so that one can discern their likes for the (lumping together here) Class D amp sound.