Something that is really missing from vred is the ability to round the corners of geometry. In mental ray the round corners shader allow you do this. It is a shader trick that adjust the normals rather than actually subdiving the mesh. I know mental ray have a patent for theirs but vray have one(last time i used it it was not great), also modo have a really great one, along with the newly announced Octane 2.0.
It is extrememly useful when dealing with cad data as many mechanical parts have sharp edges and it helps so much to get the round corner effect so those sharp edges can pick up glints of light to feel more natural.
