Whether you consider the KP to be a step up from the K-3 & K-3II depends on your priorities.
The KP's high ISO image quality and range is significantly improved, and there are some neat additional features and upgrades. But, the K-3 and K-3II have a larger buffer for burst shooting (and a slightly faster burst rate, too), dual cards, longer shutter life, full magnesium alloy build (
including the top plate), IR remote capability, top-plate LCD display, considerably longer battery life, and the K-3II has built-in GPS. Plus, the larger form-factor and grip is, arguably, better suited for larger lenses - though that's subjective, to some extent.
Not all of those features are essential to me, but losing them wouldn't feel like a step up, either.
I wouldn't
switch to the KP, although I certainly wouldn't mind owning one as an
additional piece of kit - if only for the improved high ISO capability, which
is impressive. I tried one out at a show earlier this year... Nice camera, for sure
Originally posted by pakinjapan K1 is the real step up.
Only if the format works for you. Wildlife and sports shooters, for example, would probably disagree