It's not just a little bit better than the d7k, it's a lot better.
This is a raw image, taken with a 40mm Nikkor macro lens.
Unfortunately, it almost impossible to see on a blog/website how stunningly sharp this is.
It's basically the d7k body, a little bigger but not very. It feels the same in the hand as to weight. The buttons are all in relatively the same places. It takes the same battery. I took the chip and the battery out of the d7k when the 600 arrived so I could just go out and shoot.
It's happy with an FX lens or a DX which is framed in the viewfinder so you'll know how cropped down the image is.
I know there are nitpicky little things some people will glom onto and complain about but if you just want to go out and shoot and get a fantastic image, this camera will do it. I don't know about shooting in caves or sporting events or hanging upside down off the Eiffel Tower--those people probably wouldn't be happy with anything.
Anyone want to buy a slightly used D7k? I'll include the 55-200 zoom.