I think you will not regret it. I just got a similar deal on D700, replacing D90 (I also have D7100). Low light performance is unbelievable and I love the size/feel of the camera. I expect D700 to complement my D7100 when I need extra low-light performance (weddings/graduations and other celebrations). As such I don't need too many FX lenses, only what is needed for low-light (I already have an older 35-70mm 2.8, 50mm 1.8G, and Tamron 90mm 2.8). D7100 on the other hand will be for detailed work (macro, birding). Portraits can be done well with either camera and I will be comparing the results.