My girlfriend just recently upgraded from a D3200 to a D5300 and I have to say the D5300 is pretty sweet. While I wouldn't give up my D7100 for one but it really is a damn fine camera. It's had the OLPF removed, which is nice, and the image quality has been very impressive with average glass; put a really good prime on it and it really shines.
With the upgrade you'll get significantly more focus points and more cross-type focus points, which is always a big plus. And you'll get that sweeeeeeeet articulating rear LCD, which will be much sharper than your 5100's was, one of things I sorely miss on my D7100. The 5300 will shoot a little faster and have a faster max ISO... Lots of little upgrades. We find the GPS is nice touch but the wi-fi is about useless.
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