The most important upgrades, to me, are the superior image quality and autofocusing.

what a pleasure this upgrade has been

A fantastic upgrade from my older D80.

Stellar upgrade in sharpness

The autofocus system is a significant upgrade, with more focus points and an upgraded tracking system.

The Tamron 17-50mm f/2.8 (non-vr version with the AF internal motor) is also very good on this camera (and less than $300).I would recommend this camera as an upgrade from the D3100 (or earlier) or D5000, but not necessarily from the D5200 or even the D5100 which are both very similar (although the D5100 has a 16mp sensor and is about 1/2 stop behind in the high ISO dept).This is really a terrific camera.

A worthy upgrade to my aging D40

My previous camera was a D80, so this was a significant upgrade and well worth it.

A nice upgrade from the D5100.

After a few thousand shoots in a recent trip, I would say it is a reasonable but not necessarily compiling upgrade from the D5100 and probably even less an upgrade from D5200.Pro

This Nikon D5300 is a modest upgrade from the previous model, but it's just as worthy alongside something like this Canon here: http://amzn.to/1GCdVBnPROS:24-megapixel sensor with no optical low-pass filter

Good upgrade from a Nikon D3100

Significant upgrade from a phone camera.

Overall my fellow Nikon geeks, this is a great upgrade still within most of our financial means

Awesome Upgrade from an Exhausted

Love my camera upgrade....has so many features I still need to learn, but have used it for 2 photoshoots so far and loving it!

Shooting with a good sharp lens like the Nikon 85mm F/1.8G, the detail at 100% zoom is amazing

I will say that as fast as those cards are, you almost want faster.

I have a lot to learn about it's use and am the functions, as well as how to take a great picture

ISO then you might find the camera frustrating as you sometimes will have to navigate the software on the camera.