You're right, how would we ever know.Good question, in fact, a friend of mine (he is probably one of the first clients of ACME) gave me the same feedback, that ACME's leather is top notch, but still a bit below YF, Aurum, and a couple other tier one makers.
When I read about ACME's review from Jesper, I was also thinking if he may have received a "better" shoes than normal customers. But I guess that'd be hard to find out.