There are a lot of differences between the two. Some have been mentioned, like the weather sealing and 2 card slots, but the d7100 has quite a few additional improvements over the d5300. Some are the larger OVF, higher resolution screen, more focus points, more cross type focus points, higher max shutter speed, 5 frame bracketing, and the 1.3x crop mode. The d5300 does have the swivel LCD and the built in GPS. It also has slightly better ISO due to it having the newer Expeed 4 processor instead of the Expeed 3. When I first got into Nikon I bought a d5200, took it home, tried it out, returned it and bought d7100. The d7100 has some features that are important to me that the d5x00 series doesn't have.