I used to own the Ayon Crossfire III and it was a quite good sounding amplifier. It is perhaps a bit "matter of fact" compared to some other SETs but it had very good bass, dynamics, transparency and soundstage. Tone was ok but improved significantly by changing the input and driver tubes. I think the whole range of EML tubes (EML makes the Ayon tubes) are more on the neutral/matter of fact presentation compared to some other tube types I have tried. The Amare Music I had used the EML 1605 output tube and the EML 20B as a driver. It had a little bit of what I heard in the Ayon but was significantly less of everything you would want in a good SET.
That said, the Aries Cerat and Amplifon are both, IMO, significantly better than the Crossfire III even though in isolation the Crossfire is quite good. The Helios has more pizzazz but it is clearly more colorful (colored?).
I have heard the other amps you have indicated from Japan but not in direct comparison. One of the best sounding amps I ever heard was the WAVAC HE-805, which is a very expensive product but sounded rather amazing...note this was at a show and not a long audition.
Kondo i have significant listening time and on the right speakers they are great but really need high sensitivity to perform their best (your Altecs would qualify). Shindo I haven't heard.
Cheers,
Brad