Class D amps

There are and many are quite good and worth consideration.

The Bel Canto ref1000m monoblocks I use are one good example. These are competitive soundwise with some of the best SS and tube amps I have heard and the combination of small size, weight and low power consumption along with bleeding edge power output and solid current delivery is hard to beat.

It really is YMMV. I got a pair of Wyred 4 Sound class D monoblocks about 4 months ago and they are the greatest things I have heard in my system thus far. IMO they are extremely transparent and convey what is exactly on the source material which to me is the highest complement you can pay a amplifier UNLESS you want your amp to color your music. I don't have any issues with its high frequency performance and they sound just as extended as any other amp I have heard in my system. The alleged high frequency issue kept me away from class D for years until I decided to hear it for my self.

I suspect the high frequency issue has more to do with impedance matching between components rather than something that it is intrinsic to all class D amps. Alot of owners of tube preamps don't like the tube/class D combo. Class D amps tend to get their best reviews when paired with low output impedance solid state amps.

"Alot of owners of tube preamps don't like the tube/class D combo"

I have a tube pre-amp and like the combo.

The thing is, you have to pick a Class D amp that is designed to work with a tube pre-amp (ie higher input impedance). Same true for other SS amps in general.

For example stock IcePower Class D modules are 10K ohm input impedance unbalanced. Not great for a tube preamp. Older BelCanto Ref1000 falls into this category. Many lower cost Class D amps do as well.

Wyred 4 Sound and newer (and more costly) Bel Canto ref1000m using similar 10K ohm stock Icepower modules are designed to work with a tube pre-amp. Input impedance of Wyred is ~ 64K ohm I recall. BC ref1000m is 100K unbalanced and 200K balanced.

The digital amp company makes a really good class d amp. They have a model called the 4800a which is being discontinued and the cherry plus is also a very nice amp from this company, I think if you are considering getting a class d amp you should put them on your short list, just my opinion, Kent

There are class T(TriPath) that I personally prefer over the class D.
Being a studio tech hobbyist, got used to clinical and clean sound to evaluate a recording quality. Learned to appreciate Sunfire class T amps for these abilities of thin details, instrument separation, speed and muscle power.
Amps such as W4S have high enough impedance to be driven by any tube preamp with ease. I would though recommend to use fully balanced tube preamps.