Woohoo it finally came in this Saturday! Haven't had a lot of time to use it yet, but so far I'm loving it. It's just about everything I wanted to have improved after my K10.
Aside from the obvious things like high ISO performance (which really is stellar though) and improved AF I'm also really liking the ergonomics. My hands are quite large and thus I never really liked the K10s shallow grip, but the K-5 is just great. Fits like a glove. Another thing that really stands out is just how quiet the shutter sound is. Haven't heard a quieter DSLR yet.
I'm happy