i went from a 5300 to a 7200, the 7100 and 7200 are pretty comparable, looks like the 7200 does a bit better with high iso, i think that is really the main difference that was important to me, i also think it has a improved focus system which also sounded good.
i really feel that i get better images with my D7200, and the 7100 should be pretty comparable to the 7200 overall
the 7200 body is nice, much easier to get to some settings quickly, i feel the colors come out nicer for some reason, over all image quality is a little better IMO, i can use a faster shutter speed when using a speed light with the D7200 and there are also quite a few other little things that i like withe he 7200
the D5300 is a very nice camera, i got lots of nice photos out of mine, it did well in low light too but i do like the 7200 allot more. but i was overall happy with the 5300 but always kind of wished i would have got the 7200, one day i got the itch to go out and get the 7200 and i am glad i did