Thanks, it's still a work in progress, but I'm getting more comfortable with the workflow. PBR changes things as before I would separate the model depending on texture, now you don't have to. Although now you need to use masks to keep the dielectric and conductive materials apart.
Here is the node setup for the dust test image:
For dielectric materials like the red plastic of the material ball you almost always want to use a glossy node. I just plug in the diffuse/albedo, specular/gloss, bump/normal maps generated by 3D-Coat into the the node. I have found that the diffuse comes in a little dark, but I don't have a good way to determine how to adjust it. I have heard that the 3D-Coat devs are fine tuning the PBR diffuse to help with this but I don't know when it will change. I have also heard that there is the same problem with other PBR apps like Substance and DD0.
For conductive materials I also plug in the maps to a glossy node but in this case you set the "Index of refraction" to 1 or 8. This sets the fresnel reflection up, but I don't think it matters much which one you choose, they both look the same to me.
To combine the two you need to add in a mask. In this case I combine the two workflows together ("gloss /color specular" and "gloss / metalness" ) and use the metal map for the mask. So you mix the two glossy nodes together and use the metal map to control them. The conductive node connects to the first pin and the dielectric node the second pin. The 3D-Coat devs have added in the new beta version the metal map export to both workflows which makes it a little easier to output it. Before you had to change modes before you could access the metal map.
The dust is an additional layer that is mixed in. In this case I use a custom smart material to generate the dust mask. The mask is used to control the mix node, the same as for the metal map. The dust itself is just a diffuse materials with a falloff so it has white highlights. I also used the mask as a bump map to give the dust some depth. The dust material gets plugged into the first pin, the combined material in the second.
Hope this helps, it's not very difficult to setup once you get the gist of it.