Hello Audiofankj.
I think I would have been careful to say the amp in my hands have blown the competition away in my system. Even though I never said that. :)
I don't think I stated on this thread, my speakers are the 1ohm Scintilla. On general discussions like this, I am leaning on the more normal systems of yourself, and of Strajan, the reviewer of 6Moons. Systems I figure readers can identify with more.
Frankly, I think it is a feather in Henry's (H2O) hat, that it performs so well on the most difficult speaker load devised.
I had moved from all tubes to tubes and solid state when I switched my Apogee Stage speakers to larger Apogee Duetta speakers. They are both nominal 4 ohms, but there's a lot more panel to drive. I tried the Pass X150, and liked the results. There was a nagging high frequency beam I never was able to rid of. At the time, it was my best system sound.
In anticipation of getting the Scintilla, I bought Pass Labs X600 monos. On the Duetta, it was more dynamic, and warmer than the X150. At least one listener liked the X150 better.
The Scintilla is not just another Apogee. It is a partial bipole. It's presentation is simply music in the room. Any amp that can push the 1 ohm Scintilla is wonderful, in my book. Never mind one Pass mono had heat stroke a number of times. The sound was bold, and dynamic. The bass was fugitive, however. The sound was the best I'd heard in my home.
A fellow Apogee owner mentioned that he had heard the little known Acoustic Reality eAR amp on his Scintillas, and it was great. I couldn't see why. The Pass's noise level, and distortion stats are way better than that of the eAR.
I gave it a try. He was right. The diminutive eAR gave up on some depth and wall of sound, but with the help of a big gulp preamp, it lifted a heavy veil I didn't know was there. It also gave the bass voice. It was the best I'd heard in my home.
Enter Henry Ho, builder of class A amps with enormous reserves. I asked Henry if he'd try the ICE module, in an amp of his device. He did, and loved it. Several months later I got my H2O Signatures.
The H2O has a power supply that would do a class A amp proud. Henry said, with the ICE module, "The highs are very hard to get right." Get it right he did. The whole of the spectrum sounds quite natural. With it's big analog power supply the H2O improves on the eAR. It gains in bass authority, depth, slam, naturalness, and weight.
I never have written a review of my amps. When I got them, they were the only Signatures around. I wasn't even sure if they were going into production. There are great reviews out there now. I'm willing to answer questions, or provide more details.