Product review (5 stars): Excellent product.  Highly recommend.
We have saved much more than the cost of getting our dryer vents done professionally.  The first time you use it, there is a learning curve, but this works very nicely and went through our 2 90 degree bends and 27 feet of dryer duct very easily.  We live on the third floor of a condo, so accessing from the outside is not possible unless you own a fire truck with one of those extendable ladders!  You can get extra extension rods online from Walmart.