Picked up my Loxia 50mm today and took a few quick shots. Oh my! Instantly my favorite lens for the A7R (and I suspect it will be for my A7MkII as well). In my 45 years of photography I have literally shot 100's of manual and auto focus primes (Leica, Zeiss, Nikon, Canon, Olympus, Minolta, etc.), and IMHO the Loxia 50 is as good overall as any of them and much better than most. I have the Sony/Zeiss 55mm f/1.8 "baby Otus" and love it as well (largely for its wide aperture sharpness), but it makes more clinical images compared to the classic rendering of the Loxia.
The Loxia balances perfectly on the A7R. The lens is mechanical perfection. Focus is easier and faster than any other MF lens I've ever used, especially with the A7R auto zoom in feature when you turn the focus ring. Colors are amazing. A tad soft in the extreme corners when I shot a brick wall wide open as you would suspect, but otherwise very sharp and contrasty. Very, very usable in real life straight from f/2. Wow--can't wait for the Loxia 85mm and 25mm !!!