I have the k20d, my son gave it to me for my birthday 3 days before I embarked on a trip to Camerons Corner. Steep learning curve but I have to say a very user freindly camera.
The self stabilising with zoom is excellent and the detail in the photo allows for cropping and zooming for better detail on wild life and fauna.
As for speed I have found it is not a problem, i took many action shots of motor bike while on the trip and they all turned out .
The camera is ready to use very quickly after turning on which I found to be very handy.
I already had a pentax slr but it was the old style, this one is excellent.