I've just entered the NEX system, picking up a NEX6 camera with standard power zoom, and also partnering it with a Voigtlander 15mm, used with a Leica M adapter.
I specifically chose the NEX6 over the NEX7, as the behaviour of the NEX7 sensor in the corners appears to be extremely poor when partnered with lenses with small rear element to sensor distance. Examples I've seen of my Voigtlander on the NEX7 have been disappointing, yet the results I've had from the NEX6 have been excellent. Indeed the corner results on my NEX6 are far superior to the lens when used with my old Panasonic GX1, even though the smaller sensor on that might imply less corner issues.
My question would therefore be whether the NEX7 is a wise choice for lens testing, when Sony's newer cameras appear to have a much better anti-aliasing filter/micro lens/filter formulation which fixes these corner softness issues.