This one was done fairly recently, so the mods are probably gonna close it down. I think it turned out that, though they seem very similar, MM can do everything Vision can (strength, energy blasts, intangibility) only better (except for the intangibility, which vision can hold longer).
And double-yep, MM is everything Vision is (eg invisibility, phasing, heat blasts, etc), only far better (plus MM has abilities that Vision doesn't have, such as telepathy, shape-shifting, telescopic and x-ray vision, and such). And MM's strength can keep up with Superman's for a while.
MM would literally own Vision.
actually, i think Vision might be a little stronger because in a recent Marvel Encyclopedia it says that Vision (in exact words) can increase his density up to the point where he weighs 90 tons and can lift more than double of that. I doubt MM can lift more than 180 tons. Plus Vision does have X-Ray Vision, and although he doesnt have heat vision, he can shoot heat waves from the diamond on his head which is practically the same thing.