Product review (4 stars): Great at reducing the heat bill
Your paying for the heat anyway - so why not heat your house.  For the price it does a great job - yes it is plastic, but what do you want for 8.50?  The screen does not capture all the lint and causes some dusting.  I fixed this by placing a cut to fit piece of cheese cloth on the outlet and covered with the screen.  When you feel the air flow diminish when your running your dryer, simply remove and clean the lint off the piece of cheese cloth and put back on the vent outlet and screen over top.  This is about every 6-8 loads of laundry.  No big deal - just like removing lint from your dryer screen.  I have not experienced any moisture issues that others have said.  I've been using this for two years now.
Would definately recommend to friends.