I got a K100D two months ago, coming from a half-new Canon P&S. Even now, some things does bother me, especially when reading about the K10D.
If you have the money, and know you are going to use it a lot, I would have picked the K10D.
(I didn't really have the money, and the K100D was under half the price of the K10D-equivalent Samsung GX-10, so it does not bother me too much. Still, missing especially speed and some functionality. Image quality wise, I don't care, though.)
PS:
I suppose that is always what it's like. Wanting something better and newer.