Working on procedural animation and an all new animation state system currently, so no pretty lighting for a while. Just using a simple 'skylight' hack in the meantime. BTW the FbxSdk for Linux works pretty well, which is nice as I didn't have to make a reverse engineered importer just for this.
Note all these are using faked IBL without AO and no shadows to see the difference better. I'm not saying the implementations are 100% either. :D
Here's what it looks like with a Beckman Specular BRDF, and minor GBuffer shader tweaks -- similar to the Order 1886:
Burley aka "Disney" -- similar to UE4:
"Kagura Default" which is a GGX + Normalized Oren-Nayar -- similar to Deep-Down reveal:
Beckman + Oren-Nayar vs GGX + Oren-Nayar with paused camera ( for use with photoshop )