To give you an idea of the focus speed of a DSLR, Pentax Forums have this video to view. They also have a couple of others that show the difference, if any in the speed of their two Auto Focus systems. This series is part of the Pentax Kr review, a camera I may well get to replace the HS20.
The lock on speed is very very fast, and the Pentax K5 is even faster.
If the HS30 is able to approach these speeds I may well reconsider my purchasing choice for this year.
The full Pentax Kr review can be viewed here.