Substance Painter Iray vs Superfly

Below is not a very scientific comparsion, I work in Chimp mode (assuming chimps have access to computers and beer) ie iterative rather than scientific approach. Loaded the Coalition's Katana into Poser then exported it to Substance painter via FBX. Created the textures and rendered in iray. Then exported the materials back into Poser and using BBs EnvSphere loaded the same environment lighting from SP as the HDR map. Then adjusted the lighting (gamma/intensity) to get similar looking levels. Its not exact, not being able to see the HDR background in Poser made it difficult to align. Overall impression - Iray was more reflective (may be different F0?) The UV map fail on the Poser render was interesting but may have been an issue with the FBX export.