I have the 1DX, 5DIII, 5DII and 7D bodies and the 85mm f1.2L II. I read Bryan´s article and wondered about the same thing. I do not have any scientific equipment available to help me assess this, so I just did a subjective comparison with the 3 bodies (did not try the 5DII). To be honest I cannot really detect any significant difference between any of the bodies in good light. But the 5DIII and 1DX seems to be faster in locking AF when the light goes down.
I agree with Bryan that this lens works well also for sports, as long as you don´t have too fast objects moving towards you. But the very shallow DOF with this lens at f1.2 is a challenge and you need to shoot more to get a fair share of keepers. But that is the case with all other use for this lens as well. I also think that the f1.2 capability is the only reason for using it. At 2.8 and above I use the 70-200, which has significantly faster AF.
When focus is right I don´t know of any other lens that can challenge the outcome of the 85mm 1.2L II.