I'm not saying the cameras are not good. But its all marketing to create that need for people to have new systems. I was sucked into the A7 hype, but for my needs the newer system offers too many compromises and will be looking at Nikon instead. Same sensors, but proper glass lineup.
The huge advantage of the Sony is the ability to use just about any lens with it including all my existing Canon mount lenses. That is HUGE and it is something Nikon cannot do.