Substance Painter is what I had imagine the next step for 3d painting should be. Being able to paint multichannel is very efficient. This is something that Mudbox is lacking. I urge the developers/programers for Mudbox to implement this in. I think Autodesk can try to bring Paint FX into mudbox. Imagine how powerful it will be, being able to paint hair onto the model and bake it down. This will definitely be Mudbox's answer to Zbrush's fibermesh. Think of the the possiblilities, since paint Fx has a lots of parameters, it is procedural which is great for production when you need to make a lot of iterations.