When comparing VRay vs Radeon ProRender, the Slant community recommends VRay for most people. In the question“What are the best renderers?” VRay is ranked 2nd while Radeon ProRender is ranked 3rd. The most important reason people chose VRay is:
It's one of the fastest rendering engine of the "time"
Ranked in these QuestionsQuestion Ranking
Pros
Pro Speed
It's one of the fastest rendering engine of the "time"
Pro Can use CPU and GPU at the same time
Unlike other renderers, Pro Render is capable to using CPU and GPU at the same time, increasing render speed tremendously. Pro Render can also use your system RAM and GPU vRAM at the same time to increasing efficiency in complex scenes.
Pro Hardware Agnostic
Runs on AMD, Intel, and NVIDIA so you don't have to worry about it on some hardware.
Pro Free
Radeon Pro Render is free to use.
Pro Final and interactive render denoising
Pro Embree based acceleration
Pro Vega GPU arcitecture support
Cons
Con Learning curve
Learning this engine can be tedious sometimes. Specially because you can choose between several indirect lighting (or global illumination) techniques.