Welcome to the Forum. The K-5 had some issues at the start, but all the reports indicates that this is fixed.
I have the K-7 that is exactly the same body as the K-7. It is a very rugged body and I had no problem in 2 years despite a few hits and misses. I can recommend the K-7/K-5 body for its solidity.
I moved from P&S cameras to Pentax K-7 because of the superb viewfinder, weather resistance (at a decent price), the continuous shooting ability, and the body handling. Since I discovered that all Pentax lenses can fit on the K-7 (and K-5), giving me a great choice of excellent lenses as moderate prices. This is very important because, as you know, 'good glasses' (good lenses) are the key of outstanding IQ.
In your position, I would jump to the K-5 without hesitation.
In addition, there is a great Aussie community at PF!!!
Hope that the comment will help.