Sat 04-May-13 01:39 PM | edited Sat 04-May-13 01:44 PM by RRRoger
I had a 5D2. The immediate difference you will notice is the faster more accurate focusing of the Nikons.
You need to get "Hands On" before buying any camera.
Frankly, coming from a 5D2, I would choose a D7100 first then the D600, and finally the D800. That is if all I did was read specs and reviews. Plus you notice they are rated with the lowest price first. There are a lot of reasons why they are priced the way they are.
The D7100 is the go to for longer distance shots.
The D600 actually seems to perform best at High ISO/ Low light. The grip is too tight and hurts my fat fingers + it lacks an AF-On button, but my second shooter (wife) prefers it over the rest.
The D800 is all around, the best camera I have ever owned. I often shoot Mid size images at Events to save file space and to facilliate e-mailing pictures.
I have all three cameras and think their worth is equal to their price. If I had my druthers, I would trade the D7100 + D600 for a D800e.
As for build quality, I prefer all three Nikons to the "Pro" 5D2.