Product review (5 stars): Very pleased
I installed this vent over the summer and have waited to review until we had some cold days to judge.  Installation was simple and directions were clear.  I periodically check the floating cup for buildup and have not seen any significant issues - it always falls into place to seal the opening.  It is frigid weather today(4 Fahrenheit) when I checked), and our dryer is in the bathroom, and I was so pleased to find the dryer was room temp and not an ice cold heat sink like it used to be.  I couldn't be more satisfied with it.  I had none of the issues mentioned in other reviews.  I also bought the Battic flue pillow for my fireplace - not very attractive or discreet, but effective.