Gopher - to date I have only tried Core Audio's power supplies - I've got one on my Mac Mini and one on my DAC, with outstanding results. A friend of mine, however, has auditioned the amp and says it is like nothing he's ever heard - he's going to replace his beloved 2A3 SET amp with it.
While he says the 2A3 is warmer and does holographic imaging a bit better, he added that his impression was that this is because the Core Audio amp was too quick and resolving to render a holographic image, and in fact that it made the whole idea of a holographic image seem a little artificial now that he's heard this amp.
He says the Core Audio amp delivers a presentation that is more real and life-like than anything he has heard before - incredible speed and what he calls "extreme harmonic richness and tonal density"... The sense of uncanny reality is especially strong with the human voice, apparently.
I'm going to have my amplifier by the end of this coming week, hopefully, and will post my impressions as soon as I can.