The Samsung NX200 has above-average JPEG processing for a sub-$1,000 camera. Combined with its relatively clean images off the sensor, its noise profile is quite good. The eagle-eyed will still see artifacts--especially in dark stretches of high-ISO-sensitivity photos, like this, and on edges. But overall I was really impressed with the quality of the noise reduction and compression, as high as ISO 1600 on some photos.
While the callout is enlarged to 300 percent so that you can more easily see what I'm talking about, dark areas in high-ISO-sensitivity images, both raw and JPEG, are riddled with white spots. While these types of spots aren't unusual, they do tend to be larger and less frequent within an image. (I originally thought my monitor was very dusty and tried to wipe them off--that's what it looks like.) You can probably only see them at 50 percent zoom or higher, though, and if you apply a little luminance noise-reduction in the raw processing they disappear.
I wouldn't count on shooting clean images at ISO 1600, either raw or JPEG, but if you're willing to live with some graininess then the raw isn't bad; it retains saturation and color accuracy. Here you can gain a lot from shooting raw, as the JPEGs have a lot of color noise.
(1/60 sec, f1.8, ISO 1600, AWB, spot metering, 85mm lens)
Samsung's 18-55mm kit lens is very nice. While it doesn't seem exceptionally sharp overall (the center of the frame is about the same sharpness as this), there's also not much distortion, as you can see by this edge-of-frame example.
(1/125 sec, f7.1, ISO 100, AWB, spot metering, 18-55mm lens at 40mm)
This problem with exceptionally bright, saturated red and pink hues looks like a result of JPEG clipping. When I brought the exposure down, it was apparent that the camera had retained all the highlight detail in the brightest areas.
(1/250 sec, f2.8, ISO 100, AWB, spot metering, 85mm lens)