I've been playing with this synth a bit lately, trying to talk myself into selling it now that I have the Gotharman Anamono X, but it's too interesting to let go. This thing has a really interesting step-square wave that lets you modulate PWM along with the size of the step at the same time; very neat.
This synth has a really unique sound that I like best when it sounds like it's breaking up. I like applying just enough FM to make the oscillator act a bit wonky, but not too much. Its overall character has a brightness to it that isn't fatiguing to the ear; reminds me a lot of the Nord sound at times. Gain staging is ultra important with this synth I'm finding. Reminds me of how I handled levels on the A4. The Xenophone has a tendency to sound hot; like it's always overdriving the filter a bit.
Just wanted to share some more experiences with this interesting synth since there isn't too much info out there.