Product review (5 stars): Excellent product.
I have used these for many, many years.  It is a great product, easy to clean and have never had any critters get in the dryer vent.  I recently had my house sided and had the vent put on that matched the siding, which looks good but is a pain to clean lint off plus I worry about those furry little critters venturing in!  So I got another one of these, will paint the same color as siding and will be putting it on in the Spring!