though i still fell the a7r is never going to cut it for a professional and his work, it is a camera he will grab and bring out for his own shooting.
And i must sat the SOOC jpg from the a7r is way ahead of the 5d3 even with the best L lens and thw raw files have much more capabilities than the 5d3
this is my experience with both cameras...
Funny I feel it WILL be fine for my professional work..
I tested the A7 quickly and found it focus certainly fast enough for more considered work like static portraits, even some fashion and definitely still life/ product shoots and landscape / general location work. Am looking forward to hiring one to test on a shoot next year. I feel the sensor will give me much more to work with in detail and DR terms.
However I would not really think of using it to do an more docu, or live freeform shooting work. And sports should be fine as I do a lot of skateboarding images, but generally I'll compose light with location flash and lock the focus off to get the shot I want rather than run n gun.
It all depends on how you shoot, not much will come close to the 5D III or 1Dx in AF & speed terms if you rely on that all the time.
Horses for courses no camera will do all, I used to shoot a mix of mainly MF film, 35mm film and sometimes 5x4.
There were never really any cameras that could do it all and dont see why we should think there is thesedays.
In the past deciding which camera, film, lens etc to use for the required shoot opens up your creative choices and makes you focus on what you can achieve with the tools, situation and some creative grey matter!
Overall I was really impressed with how it felt and worked - reminded me of using an film Canon A1.