I wouldn't even worry about shutter life. It's doubtful you'll reach 100K clicks on the shutter (unless you shoot in your sleep
)
I just bought a K-5 on Monday with a 40/2.8...after having a canon 50D (that i bought in june last year..too many noise and slow AF issues on mine). Nonetheless, the k-5 is simply amazing. the amount of in camera tweaking you can do is unparalleled, and matched with the DA* AND FA limiteds...it can compete with the "pro" DSLRs by the other manufactures.
And yes, even though nikon and canon etc have more lenses...but, i don't care, you only need like 3-4 "premium" lenses (DA*, FA), you
DON'T need 87 different lenses...that's just silly!
I
HAVEN'T had any of those ill-fated AF issues, Low-light focusing issues, sensor stains, external/wireless flash issues, or anything. I'll provide the link below to my
flickr page where i did some tests shots and you guys can suss it out.
Don't hesitate. Buy it and love it
& quite possibly the most underrated camera in the past...decade?
dooooooo it!
suss it:
K-5 Test - a set on Flickr