I had the chance to audition both of these amplifiers in my home, driving Thiel CS2.4, using the Bent NOH passive preamplifier (TVC). I must say that the D200s worked very well for me but not the Ayres. Having read glowing reviews of the Ayre, I expected more and felt disappointed that the Ayre was not able to musically move me. Later, after I had returned the Ayres, the salesman told me that I should not have used the Hydras with the Ayre since the amplifier already has some kind of power conditioning. Sonic differences: D200 was a revelation - tremendous headroom, uncanny speed, wonderful with strings, cymbals, vocals. Details literally float in space! Come to think of it, same is true with two other SS amplifiers I compared it with - Odyssey Stratos Plus, YBA Passion 400. So for me its the D200 by a clear margin.