Nikon just announced the D5500, which is supposed to replace the two-year-old D5300. The cameras are identical, except for a few minor things.
My first question was what happened to the D5400? I guess someone in Nikon's marketing department felt that the number didn't have a good ring to it, so they skipped it. A D5500 would sell more than a D5400 simply because of the numbers on the name plate. It's also gives the impression that you're moving up two model numbers. The D5500 must be a pretty big upgrade over the D5300, right?
But it's nothing more than marketing. Camera manufacturers are really good at marketing. They do a good job of giving people G.A.S. (Gear Acquisition Syndrome). The fact is that this camera will produce identical image quality to the D3300, but at a much higher cost. Nikon doesn't want you to know that--that's why they label cameras "Beginner" and "Prosumer" and "Professional" and other titles that do nothing more than make you feel you need to buy a more expensive model.
What are the big improvements that the D5500 offers over the D5300? A touch screen. That's cool, but they take away GPS. So if you want GPS, go with the D5300. If you want a touch screen, go with the D5500. If you want both, you'll have to wait for whatever DSLR will replace the D7100, which is past due for an upgrade (at least with Nikon's schedule). Personally, I don't need a touch screen or GPS.
The D5500 also offers a minor upgrade in video quality over the D5300, but they're both 1080p high-definition. It's a very minor difference. Otherwise, the two cameras are the same.
But they're not the same price. The D5500 will retail for $900 for just the body. The D5300 retails for $800 for just the body, but can be found for less than $700 if you shop around. I found a body-only D3300 for $375, and I get the same exact image quality as the D5300 and the D5500.