I recently shipped off my Canon 5D Mark II to move my gear in the direction of the new mirror-less Sony A7R. I had rented the Sony enough times to convince myself it was a worthy swap. I think it was mostly the size of the camera and the dynamic range of the sensor that convinced me. So far I haven’t had any regrets. For those of you who haven’t heard, the big deal is that Sony, the maker of the sensor in the Nikon D800e, widely considered to be the Holy Grail of landscaping cameras, decided to put the same full frame sensor into its own model, the A7R. There are some shortcomings; mainly miserable battery life, lack of native lenses, slowish AF, no optical VF, etc.. You can go read the whines over on FM for more details. For me, since if a person wanders into my photo, I patiently wait for them to move on so as to not ruin the image, AF isn’t a big deal. Once you settle on an adapter for your lenses of choice (mine being Zeiss primes), you find heaven.
So far its been a worthy move.