Recs.
Updated
SpecsUpdate
Pros
Pro Can take super low noise, high sharpness images with Pixel Shift Resolution enabled
K1 has an alternate shooting mode that can significantly reduce noise and increase sharpness. It's called Pixel Shift Resolution. Once enabled it will take 4 shots moving the sensor by 1 pixel each time in order to capture all color information for each pixel instead of distributing it over 4. A visualization can be found here.
Pixel Shift Resolution shooting mode takes longer as it's taking 4 shots instead of one and requires a couple of seconds after the shots have been taken to process the images into one so it won't work for sports or action, but it's great for landscape photography.
Pro The K-1 + one of the Pentax Limited full-frame, all mechanical lenses is the dominant design in photography
It's not the camera alone; it's the camera and the lens together. Pentax's best lenses are the FA31/FA43/FA77 Limited series. There is no other camera + lens combination that can compete with the K-1 + one of the FA Limited lenses on a price/performance basis. It is not even a close competition.
Cons
Con Autofocus could be better
Autofocus won't be able to consistently keep up with fast-moving subjects so it's not the best camera for action or sports. Additionally, it only has 33 AF points which by today's standards is on the lower side of things and they're not spread around as much as in other cameras.