I wanted to do my own physically based shader. Rather than making complex uber-shader for all kinds of materials I needed something simple. Shader is physically correct and compatible with game engines and programs like Marmoset, Substance Designer, Painter and Quixel.
Append BasicPBR node, add it to material, plug textures or set up values by hand. There is no need for Ambient Occlusion input because Cycles renders it basing on NormalMap and/or Displacement. For best results use HDRI lighting.
Preview: http://i.imgur.com/u4LiQRY.jpg Graph: http://i.imgur.com/PcfmSwo.png
Node is based on various publications and CynicatPro tutorials.