I like my Aptus 75s files with RZ lenses. I've made maybe 20 photos with it over the last three years.
I reach for a Canon for work because of the tethering and the 1.2 lenses. I use the D800e when I need the resolution or in uncontrolled lighting. I could use the Aptus but its heavy and eats batteries, and requires powered repeaters to tether for my new machines.
D800e files need more post for people shots than the Aptus. I think of the D800e files as, functionally, of the same quality as the Aptus files. In a direct comparo I liuke the Aptus files more, but the D800e files are really close and only "suffer" when looking at both side by side. The lens used has more baring on IQ than the sensor, in my opinion.
In truth, the reason I use a certain camera is based on lens choice and handling requirements. As an example: I don't shoot professionaly anymore, just in house stuff for an agency that is for internal use only. I agreed to shoot a series of photos of coffee paraphanelia for the coffee shop by my office in exchange for $1000 in coffee. Deliverable were 10 16x20" prints, B&W, creative direction was "stark, soft natural lighting". She provided some jpegs of lighting and perspective. She gave me a trunk full of mocha pots, espresso portafilters, you name. The prints were to dropped off with a framer after she made her selects. I had three weeks. Fantastic.
I completely forgot about it. The Sunday before they were to be delivered she called and asked to see some proofs. End of day, I said. I looked around my house, no time to go to the office studio. I set up a charcol muslin under my skylight, started to break out the Aptus but thought better of it: natural light, I needed a clean 400 or 640. I had a 5D2 that was charged and ready to go, and a bunch of Hasselblad V lenses and extension tubes and a Photodiox adapter. I had sketched what I wanted to do, found the sketch, booted C1 and focused the 150 Sonnar with live view, used Capture Pilot to fire and make exposure changes, shot about 70 frames, processed everything out, used Silver EfX for B&W, cropped to 4x5 format, emailed JPEGS, received selects, final post work, uprez for 16x20 at 360, sharpened, printed on the 4880. Four hours, and now I have all the espresso I can drink, the prints look fantastic.
Not that this could not have been done with MFD, its just an illustration of what is really important to a project, and keeping focused on the goal. In this case it was a 5D2 with CF lenses. The old cliche is right, horses for courses.