Lets not forget that size and energy efficieny are particular strengths of Class D compared to Class A.
When I was searching for an amp, if there was a high power Class A amp even close in size, weight, and energy efficiency, I would have had little reason probably to go Class D.
Sound aside, these are major factors to consider is your goal is to get the most out of good but inefficient or harder to drive speakers. The absolute best sounding amp may be out there, but some people like me do not want to deal with power drinking devices that are to heavy and bulky to deal with easily.
I think the BC ref1000m Class Ds deliver a sound competitive with the best systems I have heard.
I will not say they are the best or better, but I am confident that they are competitive.
They are not cheap, but are small, only weigh a few pounds each, run cool always and I can leave them on and run them as desired without running up the electric bill. That's something worth considering if you have speakers that can benefit from a monster amp but you do not necessarily want to have to deal with the size weight energy consumption, and heat production of Class A or similar beast.
I have not heard W4S amps, but what I have read leads me to believe they are a very good value if lots of SS power is what you need.
In comparison to less powerful or smaller and lighter SS amps, the lower powered Class D amps may lose some of their unique value proposition.
BC ref1000ms are designed to work well with tube amps and also have a custom power supply onboard that might help them deliver more bass and/or handle difficult loads better than stock Icepower perhaps. Wyreds (60Kohm unbalanced) and BC ref series amps (100kohm unbalanced) both have custom input sections with higher input impedance for better mating to tube pre-amps.
The custom power supply enhancement on the BC ref amps are the unique feature that led me to go for those at considerably more cost than the similar powered W4Ss in that this is something that I determined could benefit my particular speakers. FOr some other smaller or easier to drive speakers, this might not matter as much. YMMV.
