Well, I've tried using both and tend to stick to the native PEF format. The files are smaller and you can always convert any you are worried about keeping into DNGs later. Don't forget that Adobe keep changing the DNG format whenever they feel like it.
I remember seeing a comment about file formats somewhere where the reply was to the effect that there will always be a 14 year old somewhere who'd be able to read the files no matter what.
I've been using my K5 a bit more of late and the quality of the output is really excellent. I'm a happy bunny. Just over 400 shots since it arrived and I still haven't had to recharge the battery.
But a battery grip is on it's way just in case, and so that I can have somewhere to put my little finger if I feel like it
