OK I can safely say WOW
Although I have not had too much time to play yet (run my own business and Christmas was hectic with family visiting!) I have still had a chance to get some snap shots..
Impressions? You will have heard them all before
Build quality - Feels the same as the k20 - well built and designed. Solid. I have the grip (which I had on all the time oon the k20)
Speed - Wow - just wow - Very quick focus, continuous high is incredible - lenses feel like new lenses - 16-45, tamron 28-75 and Tamron 70-200
Low light focusing - just this alone justifies the purchase - I cover (voluntarily) a few indoor poorly lit social events and the k20 always struggled - the k3 doesnt
High Iso - I've never really shot hi Iso as the k20 was pretty messy - the k3 makes ISO800 seem 'normal' and the noise cleans up in PP incredibly well.
Live view - much better than the K20 but I tend not to use it - handy when you give it to P&S users to take a photo tho!
Flash metering - Much much much better - P-TTL works! - bounce works - distance appears to be greater (mainly due to correct metering) - Using metz 54af2
Battery life - hard to say using 2 batteries, but its seems good enough for my use, probably not as light on power as the K20 tho
Overall image - seems a bit nicer out of the camera - I shoot raw - and on import LR5 shows what I think are fairly pleasing images without much work.
Menus - There is a lot more to get my head around over the k20! - will be handling this over the coming weeks
General button layout - Love the ISO and exp comp buttons - hate the metering mode button (prefer the dial like the k20) as I review the shot go to change the metering method and then nearly delete the picture! I guess its just different to the K20. Still getting used to the info menu layout, but its very similar in principle to Olympus's super control panel (or theirs is like Pentax's) which I have on my XZ2
Shutter - Is it working?
Anyway some snapshots..
Pentax 16-45
Pentax 16-45 cropped
Tamron 28-75 cropped
Tamron 70-200 cropped