As a long time professional advertising photographer and an early digital adopter, my big problem with mirrorless cameras, is the viewfinder. In high contrast situations the viewfinder either biases toward the bright light or the shadow area, leaving the photographer unable to define all that is in the frame. NOT GOOD. I would love to embrace the extra sharpness that a lens that isn't compromised by having to be designed with a mirror/prism in the optical equation (much like a rangefinder Leicas lens can take advantage of) but this is a question of compositional fidelity. If you can only clearly see part of the framed image then that is a huge disadvantage. I would love to be able to say otherwise. The technology will catch up.....I'll buy in when it does....

My only comment is what portable, battery powered WiFi storage device would you employ? And do you think, especially when shooting raw, that the Wifi link could provide the BW necessary to transfer the shots in real time in a high speed burst (not to mention the extra load on the camera’s CPU without compromising burst performance)? I just cannot see that as a substitute for a second card. Even if the combination of the camera and the remote storage device could maintain 100 Mb/sec (which is questionable), it would take about 3 seconds per shot to do a transfer - a long way from a 7 FPS burst rate.

Please make yourself aware of the mount incompatibility issues. If you have any EF-S lenses thay will NOT mount on the Canon full frame camera models. Just today I had a customer come in who bought a Canon 6D on Ebay and sold her 70D in anticipation of getting the full frame 6D. When it showed up yesterday she was disappointed that none of her 3 EFS lenses would even mount on it, she traded in her EFS lenses for a pair of full frame Tamron lenses with me today. An expense she had not anticipated in advance.