This is a bespoke manufacturer just like Cessaro and some others. Very different from Wilson, Kharma, etc. AG, love em or hate em, is the most accessible high efficiency speaker brand in the world. And that often matters to people when considering a $165k pair of amps. That's all I mean.There is a Belgian distributor for Aries Cerat (Ultrasone). Check him out.
Also as far as the ML3, it uses a tube that a lot of SET people don't go after. To them above 8 watts isn't necessary.