Realsoft 3D is still my personal favourite, but for the modelling nothing beats Metasequoia. It does just about everything right and can also be used for rendering the models directly as it has support for Renderman, and most likely is the easiest way to play with Non Commercial Renderman. Metasequoia also now has own physically based path tracing renderer that seems to be pretty good.
Renderman in action
Own PBR renderer in action
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