km25: I would rather deal with weight of the Nikons, then deal with all the factors of the A7/R. The advantage of mirror less cameras is that you can use RF lens from CZ and Leica, ect. on them. But you cannot use anything wider them 35mm. Good idea, poor execution. The sensors are good. But the rest is not. Maybe the A8/r will be a good camera. Sorry, but Sony think it through. This camera on as idea is great, but the A7 falls short.
You can use wider lenses, you just have to do a little PP to correct the photos afterwards. If you haven't already, give the camera a try for a few days and see how you like it, do not base your judgement solely on reviews on the web, especially this one.
Mister J: No built-in flash, no buy. Pity.
It is truly your loss,
Jogger: My prediction is that the camera will receive a very high score based on image quality (esp. the A7r, which has the 2nd best sensor ever recorded)... but, it will get a Silver Award because the reviewer did not like it. DPR reviews have become so predictable.
Jogger you were right, if I knew you personally I'd buy you a beer.
There are so many misleading/over exaggerated opinions and comments about these cameras that I think it's a damn shame some people are turning away without even giving the a7/R a try for their own experience, it's really your loss.