"Frankly, whenever a new version of a renderer comes out, or DS update their product I check them out. To date I have not seen a single render produced that would make to undertake the learning curve to access their environment. Maybe one day, but not at present."

Really where have you been looking? Have you seen anything from Mec4D using DS and iRay? May I ask which renderer it is you prefer?

Also you don't need an Nvidia card to use iRay, it runs using CPU as well and quite fast too on my system, especially compared to other PBR renderers.