New kit lens
The new collapsible 18-50mm lens is pretty annoying. It's slow -- only f4 at its widest -- has a shorter telephoto end than most competitors, and feels pretty cheap.
Heavy body
Though the body is smaller than many competitors, it's oddly heavier.
Back layout
Overall, the control design and layout is good. My only complaint is that the four navigation buttons on the back -- ISO, flash, drive mode and white balance -- are quite flat with very little give.
You light up my shutter button
Though it doesn't have the lights on the grip the way the K-S1 did, Pentax kept the light on the shutter button -- it differentiates between movie and photo modes -- and the one around the back OK button.
Back glow
The ring around OK lights up when the camera is on.
Side slot
The placement of the SD card slot on the grip is much nicer than in the battery compartment, where many cameras have it.
Bottom's up
Yes, it's a nice accent color, but more importantly you can still open the battery compartment when there's a tripod plate attached to the bottom.
Wireless built-in
The K-S2 has wireless and NFC built-in; unfortunately, at press time the apps to take advantage them weren't available.
Boxy
The K-S2 has more beveled edges than we're used to seeing on dSLRs these days.