DxOmark just published the full Sony A7r sensor test. And according to their measuresand ranking system the camera scores the same points as the Nikon D800-D800E (and that for $500 less). And it literally kicks the Canon5DIII in the butt.
This is what DxO writes about the A7r:
“Although we can’t provide any commentary on image sharpness at this stage in our tests, the sensor in the Sony Alpha 7R performs exceptionally and is on a par with that found in the D800 models. Given the Sony’s small size, low weight and outstanding sensor performance, it’s one of the most intriguing and compelling new additions in recent times.”
Source: http://www.dxomark.com ...rfull-frame-image-quality