Product review (4 stars): Not particularly easy to install on vinyl siding
This is a good vent and works as advertised. Since installing it I no longer have a cool draft coming into my dryer and lowering the temperature of the bathroom. I won't know how well it really works until the dead of winter when temps are below freezing.

This was a pain to install over vinyl siding. I ended up having to unzip the vinyl siding so I could cut a notch in it for the upper screw base to fit under. The vent opening should be a little longer so that you can slide at least an inch of the vent extension pipe into the base. After getting it installed I calked around the edges with silicone calking. Next I slid a small block of foam board insulation up underneath to fill in the gap where it sits over the siding, then I calked around the edges to seal it tight. Total installation time took just under 3 hours, a lot longer than I expected it would take.