My random thoughts coming from a K-5 (currently disabled so recent experience is with K-01)
I've shot into dark closets and corners several times and I'm very impressed with AF skills. I've been using fast lenses but it isn't always the center point that captures focus. The shutter seems even quieter than the K-5 classic but mine cannot be accessed to 'prove' that
The live-view feature is quite different, or else I've set up my defaults differently. In contrast-AF mode it zooms the view, snaps into focus and pops back; I do not recall my elder K-5 doing that, and I really like it
both feedback and speed are great!
Images are most excellent, no surprise and probably an incremental smidge better with newer components. I haven't faced off the K-01 and II yet.