The sensor stain issue and reports of K-5 have got a bit more silent when Christmas comes near. But since there is no official statement from Pentax/Hoya for formally acknowledging the problem and gives us an explanation on what has been going wrong, some interested potential buyers are still kept asking.. See this example today:-
http://forums.dpreview.com/forums/readflat.asp?forum=1036&message=37260532
Next, as it is not difficult to observe from the various K-5 samples posted so far (from reviews, user posts at forums and etc.), the metering of the K-5 is not that accurate and reliable. At least this is what a K-5 user complains about, who was switched from Nikon to Pentax:-
http://forums.dpreview.com/forums/readflat.asp?forum=1036&message=37258686
And then, let's look back at the semi-official DA 18-135 on K-5 review by/at the PentaxForums, in particular, the comparison test between the DA 18-135 DC and the DA 18-55 WR. Well, what can you see and find actually? All the test photos (on the resolution chart) are actually out-focused! This is not difficult to observe if you just zoom in the picture (by clicking the magnifying glass symbol) and you'll see it, I am almost sure! :-o :-(
So, yet once again, the AF accuracy of the K-5 is really not impressive, even for the K-5 with the latest SAFOX IX+ AF system of Pentax! Too bad.. Really.. >:-[
Old Bug Reports Summary for the K-5:-
Some Reported K-5 Faults (Defects and/or Bugs)