A Pentaxian at Taiwan received his new K-5IIs and has unboxed it and done some quick side-by-side image comparisons against his old K-5:-
http://forum.pentaxfans.net/thread-131884-1-1.html
(Traditional Chinese)
Well, whilst the K-5IIs images are sharper, they are cooler in tone, which was the thing I found last time. Also, a "sharper" image doesn't necessary mean that it is smoother and looks natural, just go find out yourself! :-)