I just received my copy of the optional polarizing filter for the Q (100 PL Filter). I didn't have much time to shoot with it today, but I did find this "before" and "after" example from the 5th floor of my parking garage in downtown Denver. I've owned my fair share of polarizing filters and can vouch that the 100 PL Filter is beautifully made, all metal and rotation of filter is very smooth and precise.

For those that have never owned a polarizing filter, The Luminous Landscape has a nice overview. Here's the lnik if you're interested.

http://www.luminous-landscape.com/tutorials/polarizers.shtml