Product review (5 stars): Excellent!
Okay, this product is pricey compared to all the other avialable vents at the hardware stored, but wow does it keep out the cold air!  We live in Michigan and I cannot believe how effective it is.  One thing that I did not see others comment on is the fact that when it is in use,  the heat is deflected so it does not come out in one large burst of hot air.  Our vent comes out onto a porch and in the past, the condensation would build on the wood flooring.  Not a problem now.  Excellent product.  Looking forward to painting it in the spring!