I have 2 5D2's that are both fitted with the custom grid focusing screen.
I know from using the 1DX, that things are a little different.
Let's be more than clear on the capabilities to focus on things. From my small test (10-15mins), it didn't care what aperture you used, and it didn't care how dark it was. It had 61 points, 41 of those are cross hairs and 5 are double cross hairs. AF is a totally different beast to anything you've used before.
Honestly, not quite sure why the ability to MF would be a purchasing issue on choosing this camera. For MF, i would choose the 5D2 every time - simple really - Â£3k cheaper at least - and 3 more 3mp