I haven't time to read all the 9 pages, but, if you look this image, I can see clearly splotches on the floor.
It remember me the good old problem on VRay. I would like to see 2 seconds of camera moving in MR ;-)
But ok, they have to admit, MR is dead. An don't now, but many years ago. I think in the 2006 a lot of MR user changed side to VRay.
And, when Corona will be able to have:
Adaptivity
Blend shader
Good SSS,
Skin shader,
Hairs,
GI animation flickering free for animated object and lights,
Volumetric elements
Corona-RT,
Baking texture,
fumeFX and some important plug-in
we can say bye bye to VRay =)