To me, they looked identical. Felt identical. If you mixed them up and asked me which one was which, I'd be completely lost. He then pointed me to some youtube vids of people dissecting them, and it seems like you really have to bring out the microscope to tell.
I don't know much about watches, but I'm just thinking that if they are getting so accurate...why would regular people shell out 5 figures for a real one, when you can get those for a couple of hundred bucks?
Don't get me wrong - I like artisanry, but at this point it seems like you're paying the biggest upcharge for name, and nothing much else.
(As for why my colleague bought replicas, apparently he'd wear those while traveling, in case he got robbed or whatever. Even though insurance would cover the original watch, just getting a legit one from stores/dealers has been a huge hassle. Months of wait time, etc.)