The performance of PBR is extremely low to the point where the point where i cant think of a single platform that cant run a complex scene with PBR. Most of the heavy lifting is pre-calculated so there is not much of a cost. The diffuse model is still the same, and you can still use blinn specular you just add fresnel (very fast) for rim lighting/reflections and a geometry term ( very very fast) for ensuring incoming light is not lost withing a surface. I believe epic showed part of the rouge one (star wars) running in realtime using PBR + more and that tends to be as compelx as you can get as it is designed to mimic the real world. As for stylised i have sean everything done with PBR from low poly to realism and all existing materials should work perfectly fine with PBR as long as you scrap the specular map (easily replaced). So in theory it means that porting to PBR is a case of just using the right material path and make sure you have a neutral roughness and metallic so traditional textures done look out of place without roughness and metallic maps.
As for the image you linked i assume it to be done in Blender Cycles. If that is the case then it is likely using a BRDF identical to what PBR in games approximates so in terms of results it should be identical to if you set it up with PBR, although without added effects like DOF. All pathtraces to my knowledge simulate a BRDF of some form just out of the nature of their design. Take that as you wish but i cant imagine a single style or outcome you can do with traditional rendering that cant be done in PBR especially not for performance reasons.