I recently bought the new DA 55-300 f4.5-6.3 ED PLM WR RE and find it a solid addition to the lens offerings.

The lens is quiet and fast focusing, and it does not seem to hunt, all benefits over the older 55-300 screw-drive versions. It is decently balanced on the K-3ii, but the zoom is pretty stiff and not smooth -- hopefully this will improve a bit with use.