Well, it is some time ago, I listened to Audio Valve Amps connected to Reference 3A speakers and I liked it. Good as they are, for me it is just a good tube amp. Probably they are better than most out there, I don't know.
But like most of these, they all have - more or less - the same handicap:
Speed ( no chance against good SS )
Clarity ( same, only a good midrange is not enough )
High frequency ability ( they lack details )
The Atma-Sphere, or it's Designer, solved that. I picked up a few linres from their web site ( customer comments ), because I think, it will show you the direction:
" Their reproduction of dynamics, high frequencies, timbre, timing, bass [and] control is amazing. These are easily the most fluid, grain-free tube amps I [have] ever heard. Super fast, clean and clear, natural and balanced for the whole spectrum; they are superb. I believe I had a mesmerized look in my face when I first listened to them. There is everything I hear from my Pass amps AND MORE. They give me every detail with lots of air, combined with brutal power in the bottom (without euphonic coloration), linked with stunning speed and transparency. In any case, the sound these amps produce is almost frighteningly real - clean, open, "air", wide soundstage, unbelievable detail - it's all there and then some. And: there are NO tube-related anomalies - just clean, accurate musical amplification. The real thrill is listening rock music with them, AC/DC, Deep Purple ....., these amps make you gonna dance."
Well, I did write that some time ago and I am still fascinated about them. They do a lot of things right.