My wife has the n7, I have the a77, so I use both. For sharpness the n7 has the edge, possibly because of the 24 zeiss that is on it. For studio work and tele work the a77 wins... but both have their advantages.
For me a few points about why I like both
If I could only have one it would be the a77, due to my style of shooting, but for my wife it would be the n7 hands down... so it really matters on the person behind the camera.
Shamelessly promoting my favourite painters website (my wife's )