Like Steve: I'm involved in building decks and have used differing guns (although not a Porter-Cable). The Quik Drive is nice if you don't mind having to reload every 25th screw, my personal favorite that we rely heavily on is the Muro screwgun, it holds a roll of 153 screws so you don't have to reload too often, the "T" bar handle makes it easy to push, and it takes screws upto 3 inches in length. We personally use the square tip screws, although it also supports phillips, not sure about hex though.
Here's an interesting link to see a review of different guns Screwguns.