Ok, I did one with more materials. same materials and lighting in each, and the only thing different is the angle of the HDR because each renderer interprets the HDR in a different way.

And before other people say it, I know mental ray doesn't need the settings that high to look the way this render does, but as I said before, maxwell automatically does, so its only fair. for all intents and purposes, this is a test to see which is faster on an average computer, For the maxwell one, if I had rendered it for just 10 more minutes, the noise you see would be gone, but I had already set it to end in 20 minutes.