jerryc41 wrote:
It's full frame, so you'll have one of each. If someone asks if you shoot DX/FX, you can answer yes to both questions. You can put a tele on the D7100 and get greater range, and you can put a wide angle on the D600. Put one on each shoulder, and you're ready for anything. Both cameras have almost identical controls, so switching from one to the other doesn't require even average intelligence. There are many more reasons, but I've forgotten them.
Enjoy shooting twice as much.
I did that with the Sony A99 and the A77, and love them both equally for different reasons. I also have the EM-1, which is a horse of a different feather, altogether. All are fine cameras, to be sure!