Product review (5 stars): Lint Eater
UPDATE: I have also used this product to clear the downspouts on my gutters, so it continues to save me (and my friend's who borrow it) money!

Product works exactly as advertised.  The included instruction DVD was helpful, even though the process wasn't very complicated to begin with.  My particular shop vac didn't work with the shop vac attachment, but it wasn't really necessary.  Lint got into my laundry room, but I just vacuumed it up after that.

This product saved me ~100 dollars more I would have had to spend to have a professional chimney sweep clean my dryer vent.  I don't know how it would do on really blocked vents b/c mine is only 2 yrs old, but with regular cleanings w/ the Lint Eater, I should never have to find out.  Every time I use it, I'm saving another 150 dollars!