It's been over a year since I originally posted this. I thought I'd offer my experience(s) since then.
The Wyred ST-500 is gone. It's excellent for the money and about as hassle-free as it gets but it's not SET nor is it close. I purchased a Pathos Classic MK III and pulled the stock tubes in favor of Ediswans. Reading Mr Tellig's review from Stereophile, you'd think the Pathos is a SET killer. I'd call the Pathos a good alternative but it is not as present or clear as the JAS Array I had. The Classic One MK III is also surprisingly weak for its stereo power rating. It would clip on vocal peaks such as Patricia Barber's "Alfie" from Nightclub. That didn't happen with the Wyred amp nor the JAS.
The stereo Pathos amp was nicely detailed and did a very good job with front-to-back imaging. But, it just didn't reach out and grab my attention. Even loud, it seemed like it was almost background music. I was slightly disappointed and considering my next amp purchase.
I'd read very good things about the bridged Classic Ones and communicated with Doug Schroeder about the Pathi. I had doubts that 2 would be much better than 1 but I didn't want to let the Pathos amp go as it is quite an attractive amp and easy to live with (only 2 tubes and it doesn't weigh a ton nor does it put out much heat).
I found another at a good price and took the plunge. I installed 1 Ediswan in the right tube socket and the stock EH 6922 in the left socket. The amps are up on vibrapods and power cords are Kaplan GS fitted with Oyaide 046 plugs. They are now serious contenders and can compete with the SET amp I had previously. The bridged pair is much more present, forward but in a good way, certainly not in-your-face. Detail is enhanced, rendering subtleties not previously heard in many recordings. Of course there is more power and clipping is no longer an issue though I prefer to biamp even now as it allows me to adjust the bass per recording. I hear a smoother vocal range with less sibilance than with a stereo Classic One MK III. The one area when a stereo amp is better than the bridged pair is in soundstage depth. With the more up-front sound of the bridged pair, the back of the soundstage also comes forward. It's not a BIG difference but it is there if you listen for it. I wouldn't consider it a deal breaker nor would I consider going back to a single stereo Classic One MK III-no way!
So, regarding the subject of this post, with my limited experience, I'd say SET is the best sounding amp technology. The 805 tube puts out 40-45 watts so it is suitable in many if not most applications. The ICE amp I used, the Wyred ST-500 has its strengths but sounds like an amp to me. The JAS breathed music into my room!! The bridged Pathos Classic One MK IIIs are close enough. The JAS was more palpable and transparent but the Pathi are almost there and offer more detail and much more power.
I don't see myself selling them anytime soon. What better commendation is there?