D7100 vrs D600
Well, D7100 has added the quick magnification/zoom feature to the `OK’ button on the rear thumbpad. It’s great for snappy, quick inspections at defined zoom ratios to check for focus accuracy. This feature is nonexistent on the D7000 and the D600. In addition, D7100 really improves in the areas of autofocus, shadow noise, and overall resolution/acuity. However, there may be some focus issues for some people, but for me it was technique along with camera settings. Highly recommend D7100.