Body & Design
The D5300's target audience of entry-level users will feel at home with the camera's ergonomics and controls. Aside from the slightly larger screen on the rear of the camera, the controls are more or less unchanged from the D5200 - it has a reasonable (though hardly class-leading) set of external controls. It also offers a fully articulated 3.2" LCD screen that offers benefits for live view and movie shooting.
The 4-way controller on the back of the camera is used to move the active focus point among the 39 total options in the viewfinder - it's nice to see direct access offered at this level. The level of direct control is similar to that of the less expensive D3300, meaning most functions have to be accessed an on-screen quick menu. The D5300 also lacks the touchscreen capability that we appreciate so much in products from some of its competitors. Despite its plastic body, the D5300 feels pretty solid, with no flexing or creaking.
In the D5300's class are the Canon EOS Rebel T5i and Pentax K-50. While the D5300's level of external controls feels sufficient for an entry-level user, both of these competing models provide more in the way of direct access to exposure controls. The K-50 has twin command dials, and the T5i offers a touch screen along with physical buttons for ISO and white balance.
The D5300 offers an ample array of connectors - along with the usual HDMI and USB/AV out, there's a stereo microphone input for movie recording, and a multi-function port that accepts both Nikon's optional GP-1 GPS unit (which you likely won't need, considering that the camera has a built-in GPS), and the MC-DC2 electronic cable release. Microphone levels can be displayed onscreen in movie mode but videographers needing a headphone jack will have to move up to the larger and more costly D7100. The D5300 also has front and rear receivers for the ML-L3 wireless remote. In terms of features offered, the D5300 looks pretty well-specified, though it lags behind its peers in terms of direct access to some key controls.
In your hand
The D5300 is a solid and well-constructed camera, despite its predominantly plastic shell. Ergonomically it's standard Nikon (mid-range Nikon at any rate): on the rear, a 4-way controller and the 'OK' button at its hub serves to navigate the camera's menus, set shooting parameters, and adjust AF point. Above the LCD screen to the right of the viewfinder are an 'i' button for access to key shooting parameters in the quick menu, and AE-L/AF-L button for locking exposure and/or focus during shooting. The D5300's 'menu' button is exactly where it was in the D5200 - to the left of the viewfinder on the rear of the camera.
From the top it's almost the same story - the only real difference between the D5300 and D5200's ergonomics is the deletion of a drive mode button. This button isn't replaced by something else, there's simply one less button on the D5300's top-plate. Drive mode moves to a new location on the front of the camera, on its left hand flank, near the lens throat.
The rear LCD is of course articulated, opening up a lot of options for high/low-angle shooting and video capture. The D5300 uses the EN-EL14a battery, which, according to Nikon, provides a CIPA rating of 600 shots. This represents a significant advantage over the T5i and K-50 at 440 and 410 shots respectively, but doesn't reflect the D5300's battery performance with either Wi-Fi or GPS turned on.
Articulated LCD screen
The D5300 sports a large, 3.2" LCD screen, which can be used for composing movies and (in live view mode) still images. The screen articulates via a hinge on the left of the camera's rear, and can be rotated inwards for protection when the camera is not in use. Although the D5300's display has more pixels than the D5200's (1.04 million dots compared to 921,000), that's due to the change in aspect ratio. In perceptual terms, they're equally detailed.
The Canon T5i's touch screen is also fully articulated, and the Olympus E-M10's display is hinged to tilt up and down. Pentax offers a fixed screen on the K-50.
The D5300's optical viewfinder provides 95% coverage, about what you'd expect for the class (the Pentax K-50 goes the extra mile with a 100% OVF). It has a magnification of 0.52x, which a fraction bigger than what the Canon T5i offers but considerably smaller than the K-50's finder or the electronic viewfinder in the Olympus E-M10, as demonstrated by the graphic below.