D600 Good to go!
Have you tested the D800 in studio conditions? I beg to differ. I have shot Nikon only for 13 yrs digital and I know what skin should look like. The D600 is my 10th camera so I have seen them all. I am using a D700 for the past 4 yrs and need a replacement as my shutter count is over the 150,000 mark. I did a side by side test with my D700 & D800 and the skin on the D800 looked like plastic