I would urge all those who are curious about the Sony A7 or A7R (either versions I or II) to buy one or rent one and try it out. I have heard so much about this "incredible sensor" that I decided to see for myself and bought a Sony A7 II and a Fotodiox adapter. To make a long story short, the A7 II and the adapter were returned for a refund. The Canon 6D with its totally inferior sensor, took, in my opinion, the better pictures.
It is possible for those who shoot in extreme lighting conditions to be much happier with the Sony. I did take one pic indoors of light streaming in through a window. Pushing the indoor shadows resulted in a much cleaner image on the Sony. But under daylight conditions shooting landscape shots, there was either no discernible difference between the cameras, or the Canon took shots more to my liking. Granted, it is a personal opinion, but the 2 additional stops of DR in the Sony was either not noticeable, barely noticeable, or created photos with less contrast - a negative in my opinion. I took some sunset photos hoping those 2 stops more DR would help, but the 2 stops was not noticeable at all as it would have taken many more stops of DR to capture the difference in light and dark under those conditions. All in all, I preferred the color of the Canon, and the greater contrast gave me pics with more punch. The Sony, whether because of the greater DR or because of a different tone curve, gave me pics that seemed more washed out and with less contrast.
I bought a Fotodiox adapter that did not give me autofocus on my older Canon lens. Most of the adapters will not give AF on Canon lenses older than 2006, although there seems to be some hit and miss concerning AF and which lenses actual work. The exposure was OK, but not as good or reliable as on the Canon. If you enjoy manual focus and using focus peaking, then this a better option than the Sony kit lens. I actually tried two versions of the kit lens and they were both very soft away from the center.
So, not only am I much more satisfied with my 6D, I doubt I will be upgrading any time soon.