D7100 or D700

Pistnbroke

In my experience if you are using an 18-xxx zoom its a waste of time going over about 150mm you are better cropping. That does not mean that a 200mm prime or 200=500 will not be good ..I always shoot at 5.6 or 8 with auto iso 200-6400 in Aperture mode ..tens of thousands of pics at weddings (dark to sun) without problems. I will send you my web address with 40K+ photos to examine

In general is you look at DXO sharpness ratings you will see that putting the same lens on a DX camera gives less sharpness than on an FX but do that with a D700 and D7100 and the D700 comes out lower every time ...So you did right D7100 rules