First, the really good news. Both the D600 and D800/D800e are fabulous cameras, with superb image quality in each case. I wouldn't worry too much about pixels. If you do the math, a 1/3 stop increase in shutter speed would equalize differences if you're looking at 100% views on a screen. In real prints, there's no difference. The functional descriptions in this thread are very good, and should be your driving factors, coupled with price and (a little bit) weight. In terms of size, I don't notice much of a difference nor do I think others would perceive one if you were using one. I have no problems traveling with either camera and wouldn't perceive either as "tripod queens". They're just not. The ground rule I've espoused for years about 1/2*focal length as a minimum handheld shutter speed (without VR) remains a good one.