My comment is not about circuit topology but sound quality, the reason so many people like the Shindo sound is the lack of artificiality, natural tone colors, and its overall musicality, kind of like an SET type sound that is really good SET amp produces, natural and musical.
Too many preamps or amps for that matter can take music apart and separate it into many distinct parts, which can sound really spectacular like great hifi and not music.
A really great 300b based amplifier sounds natural and musical, the Manley sounds this way, so does the Shindo, it is less to do with just using a particular circuit but the overall geshstalt of a design. There are solid state amps that sound like tube amps and tube amps which sound like solid state.
Personally the idea of using un-obtanium for parts is a scary idea, as parts age the do lose sound quality and reliability, to base a modern product on 40-50 year old parts seems awfully fool hearty. What if in 10 years you need service and that particular part on 50 years old is not available because they used them up or the part has failed due to age what then.
I think you have to take into consideration with any electronic device the future and serviceability issues which may arise, please don't take this as an attack, this is just an opinion, it it the same with a rare vintage car yeah it is cool to drive it once in awhile but I wouldn't drive it every day.
Yes Shindo does have a distinctive sound however, that doesn't mean there aren't other products which can produce a similar sound either.
Listen to a Mastersound SET amplifier the 845 sound great, the 300b doesn't and tell me if it too doesn't have a similar quality to a Shindo.
My point is simple there are many ways to skin a sonic cat.
