Product review (5 stars): This product is worth having.
This thing works exactly as advertised.  My dryer vent is nearly 25 ft long, and I had to purchase the extensions, but I was able to give the thing a thorough cleaning.  Next I moved on to the gutter drains in my yard.  Same story there.  I used the included "crab claw" accessory, and pulled out yards of roots.  Excellent results all the way around.  I recommend this product.