EvanK, the Nikkor 50mm AI-s 1.2 is, indeed, a challenge. I bought mine, and a Novoflex adapter, as an experiment to try on my Canons. With some of the resulting images working very well, I then purchased a pre-owned Nikon FM3A, to experience manually focusing with the benefit of a proper view screen. I think I like my "full-frame" Nikon! Who needs digital, anyway?
Do the pro-level Nikon cameras not have quite good focus confirmation, in the viewfinder, that will work with AI-s lenses? That would surely be less difficult than what I was doing with the Nikkor on my 7D, with no electronic connection.
Anyway, the greener grass I see on the Nikon side is the D3s, that can see in the dark better than my Canons, according to some reviews. I have missed focus on some images at two crime scenes in the past two weeks, and not fully realizing how badly until reviewing the images on the monitor later, at the station. (On the other hand, I am not so sure I would want to risk toting a $6000.00 camera on patrol.) Of course, unless I sell a quite substantial number of firearms, which would be at a loss, I will not be able to afford a D3s, anyway, so this is just an academic exercise.