Summary: I was looking forward to using this on my trip to Fl. I got this in the mail very quickly as expected from Overstock. Initial disappointment was that the inner "C" ring right on the polarizing lens was loose and showing up on top of the glass. I nudged it back into place with a pencil eraser and it seems to be staying in place. Have not had any additional observable quality flaws...just questionable quality. Used it on my Canon 17-55mm 2.8 lens.
Summary: Best to use a polarizer when you are getting a lot off reflection from water and windows. I use it a lot in the fall for the many different colors. It will cut the your light about 1-1/2 stops. I have never had a problem with that.
Summary: This is a great filter for landscapes. I use it with my Canon 10-22 mm Ultra Wide Angle lens for absolutely breath taking landscapes. I have been taking pictures along one of our local river parkways, and the reflections in the water are absolutely amazing. This filter has made a huge improvement in my landscape photos. They are truly professional quality.