It actually comes down to color accuracy (sometime referred to as delta E). From numerous articles I've read, it seems that Canon's color accuracy (cameras like the 1Dx2, 5Ds, etc.) is far more accurate than the Sony. JPEGs are another story since they are generated by the camera on the fly, BUT color accuracy factors into the rendering, as well as how the JPEG is modified in the camera. That said, I do find that even the RAW very, given the same custom white balance. I had a friend do a head shot of me not long ago. We were having friendly banter about the better camera, my 5Ds, his Sony A7R II. In terms of sharpness, things were about a draw (though THAT might be different now that I replaces my 85/1.2 with the new Sigma!). Color wise, though, I infinitely preferred my 5Ds when rendered in LR. We also experimented with AWB. Again, Canon had the more pleasing color.
Please may differ with me, but these were what I happened to see on our little photo test, but these were our particular results.