Worst thing that's happened to me(us) is where the K-5 would momentarily freeze while metering scenes in M mode at higher ISO.
Other than that, I've never had a lock-up of battery removal moment with either unit to date.
And considering what's been written here to date, I guess that makes us very fortunate.
Anyways, I know without a doubt that every device has it's problems. And... that some manufacturers are worst than others when it comes to releasing fixes. Heck... I can't count the number of times I spent big money($300+) on motherboards only to have them deprecated in favor of a newer model without ever addressing the issues. And in some cases, these were crippling issues(Asus anyone?)
Having said that, I think DSLR camera's are amongst the highest ranking when it comes to scenario's of this nature.
ie. I've owned a D200 and lens that could never be calibrated despite having it sent-in three times for repairs.
Additionally, I've owned a Canon which was so problematic that we ended-up returning in exchange for an older more usable version.
Yes, there's no doubting the severity of the DSLR market when it comes to product distribution insofar as QC goes. But... in their defense, I will say that most all of the products do end-up being stabilized over time. Which is why I am partly excited about the Ricoh acquisition. Because here we have a company who has a very strong FW reputation.
Either way, the K-5 is doing exactly what I need it to do.
In fact... it is even more than I needed.
And that makes me very happy