Thanks! It's a great upgrade, I did it mainly for the greatly improved sensor.
All the other nice modern bells and whistles like video were a bonus.
I was disappointed with my previous camera's (K20D) low ISO shadow noise on longer exposures, which gave little leeway for pushing and pulling tones. This was a shame because when shooting in my favourite environment, I like to underexpose and pull up.
Briefly considered the 5D III, but in a practical sense the K-5 better fulfilled my requirements for 1/4 of the price of the 5D III.
The K-5's sensor makes a world of difference - you can pull up a RAW file cleanly from near black, and practically speaking that's very useful, and it's AF locks much better in low light (behind stacked ND filters), very impressed