I agree, my personal opinion is that megascans and some kind of conversion table for the "correct" values for Unreal4 will eventually become the de-facto standard go-to for most people's personal/portfolio work involving PBR. Quixel's Megascans service is one of the most interesting things that's being brought to the PBR…
Yeah, unless studios are going to profit off the content/library itself, there is very little motivation to make it public. Theres also various issues with calibration and workflow/engine specific stuff as well (you might need different values than X studio uses). A library built by various individuals is unfortunately…
It's really not all over the place guys. Metals are pretty well documented in terms of reflectance values and non metals fall into a very small range. On top of that most PBR charts tell you what doesn't fit into that range. The chart posted in the document on this thread is very good. There is no way we can accurately…