Just found this thread. I also use the A7RII and the 5DIV but mostly on totally separate shoots.
Photography is my job now, it has grown out of a hobby years ago.
I shoot all of my real estate photos with the Sony (interiors with the Sony exclusively) while I do some exteriors with the Sony + 5DIV combo, having different lenses on them.
I shoot my Sony with a Metabones IV + Canon glass. Mostly the 16-35 f/4L IS. I also use a Yongnuo wireless controller for 3-4 off-camera flashes, all Canon flashes, the Yongnuo is the Canon version too but I only need it to fire, the Sony body does not control anything, I use manual power control.
This setup works great for me for several reasons. One was DR which now is close with the 5DIV. Another is the flippy screen. Before using the Sony I had to kneel down for the best interior shooting height, killing my knees on a long day. Now I just stand, flip the screen pointing upward and shoot while holding it at chest height (VF/Monitor set to Monitor only.)
I also use the Sony occasionally for family stuff, like a week ago for a Halloween Zoo visit, using the cheap 28-70mm light weight kit lens. But I at least as much use my Canon bodies too for casual stuff.
Now, where the Sony gets no use at all is the weddings/events side of my business. Granted all quality glass I own is Canon and I use those via the MB4, operation is far from reliable enough for events/weddings. There are so many things that prevent me from using the Sony for weddings/events. Occasionally it freezes with the MB4/Canon glass combo. Battery has to be taken out to reset. It's also slower to change things, AF points for instance. One SD card slot. These days I shoot weddings with a 5DIII and a 5DIV both have dual slots. Battery life on the Sony is short. Image review is slow, especially after a burst. Servo AF on the Sony/MB4 is worse than the 5D Canons. Weather sealing is another issue. And there are a few more...
So while I love all of my cameras for one reason or another, I use them for different purposes.
Interestingly though, the Sony's shots with my Tamron 150-600mm are really great for birding, as long as no fast AF is required. I actually like it more than any Canon image with the Tamron 150-600mm, in terms of IQ. But again, there are other factors that make me decide to use a Canon body with the Tamron, the sum of which trumps the IQ advantage of the Sony.
I too noticed short after buying the Sony that a lot of things had to be changed in the setup to make the camera work properly (and at a fair speed).