I had the same decision to make and decided to buy the D7000. I own both the D5100 and the D7000. I also have five lenses including the 10-24mm,55-300MM and two primes 35MM 1.8G and the 50 MM 1.8G/ Until I learn how to shoot these cameras well on manual I seen do reason to buy full frames. My main interest is shooting Cross Country and track events my daughter compete in for Cornell University. I also shoot landscape but I need to get much better with exposure and really seen little interest in the FX cameras since I have not mastered my cameras yet.