The Sony Alpha NEX-6 delivers excellent low- and midrange-ISO-sensitivity results for JPEG images. Sony's image processing is extremely good, and images shot though ISO 400 look very clean; depending upon content they can be usable and printed large (13x19) as high as ISO 6400, and ISO 12800 when scaled down.
In its default Standard Creative Style setting, the NEX-6 produces sharp but not crunchy-looking photos with the contrast pushed a little, but not so much that you lose significant detail in the shadows or highlights.
(1/100 sec, f5.6, AWB, spot metering, ISO 100, 16-50mm PZ lens at 36mm)
Processing raw helps produce cleaner edges, especially in the out-of-focus areas, but overall the JPEGs look quite good, with no hot pixels. I did not attempt to fix the fringing in the out-of-focus areas.
The camera has a bit of trouble getting automatic white balance right on cloudy days, and I really wish it had a neutral Creative Style setting. Nevertheless, the color is very good and pretty accurate.
As with many cameras, Sony's default color settings (Standard Creative Style) push the contrast and saturation, resulting in some clipped shadow detail. It's not severe enough to force color shifts, though.