Never heard any of the Otomon Lab stuff but occasionally see them for sale on ebay. Haven’t seen any come up for sale secondhand though. Found a few reviews or threads online and the majority seem to be good.
Build quality looks to be very good and the idea of a PSE 45 amp is tempting.
I’ve bought stuff from him without problem but only second hand items. I looked at reviews for his amps and found quite a few saying they liked the amp but had to get it rewired by someone that knew what they were doing. I was put off a bit.