Originally posted by Senko Very tempting - How much of a step-up is this vs a gen-1 K3 or KS2?
Quick glance of specs seems like more a side grade.
I would say main step up from K-3 would be improved high ISO performance, articulated screen and pixel shift resolution. However, you give up flag-ship build quality (including quiet shutter), burst frame rate, get an older AF system and less capable metering. WiFi is available but has some bugs.
Compared to the K-S2, build is virtually identical but resolution is improved. You also get 14-bit RAW (instead of 12-bit), plus the pixel shift resolution.