I upgraded my D90 to a D5100.........didn't like the feel of it, especially the lever to put it into live mode for movies. Sold them both and bought the D7100. I'm as happy as a cat with 2...........you get the picture.:cat:
I've also upgraded from a D90 to a D7100. All my lens work perfectly well, but the surprise package for me was coupling my Sigma 150-500 lens with it. Super supers sharp @ f/8, so much so I can see the details on the bulb of a streetlight 100 feet away at full 500mm