I like the following from
PRSJNB on the
Pentax Forum.....
"Whilst there is considerable satisfaction to be obtained from owning the latest model, the rational side of what's left of my brain insists that the only defensible argument for buying, in this case the K5, other than one's existing camera being damaged beyond the economic cost of repair, is that it would allow one to explore a more specialised photographic genre or, by virtue of improvements in technology and/or functionality, achieve a higher success rate in an area of photography that has been of long-standing interest."
That covers everybody, I think, including the OP of this discussion.
For me, with a Pentax K10d, the extra Pixel count (16.3), the HD Video capability, the flexible LCD, updated AF system and the higher FPS rate of the K5 are the notable differences. So, for me, the K5 offers......
16Mp - my 10Mp on the K10d gives a good enough resolution to make prints big enough for my requirements
I have no interest in video at all
the flexible LCD would certainly be useful
a good, fast AF system would be a big improvement
Higher FPS doesn't interest me.
So, that leaves two things of interest
to me - a better AF system and the flexi LCD.
Just not enough for me unless my K10d were to break.