Product review (4 stars): Time Saving
I hadn't cleaned my dryer vent in about 5 years.  Yes, I said 5 years.  That's because before buying this, I would have to disassemble each section of the duct (it's a fairly short, straightforward duct), vacuum out each section, then reassemble the pieces.  Not fun, and took up a huge amount of time--something that is now in extremely short supply for me now that I have 3 times as many kids as I had the last time I cleaned the ducts.  But, I knew it had to be done, and soon.  Aside from it being a fire hazard, I would have to run every load through the dryer twice before it would be done.  This wasted even more of my time.
With this kit, I was able to clean out my ducts completely in approximately 45 minutes.  It would have taken me less time if I didn't have to try to dislodge a huge clog in the elbow (no wonder it was taking me two rounds to dry my underwear).  Now that it's clear, my clothes all dry in one cycle (jeans included!).  And since it's so easy to do now, I should be able to keep the ducts clean on a more regular basis.

My only complaint about this product is that the bristles would work better if they covered the top of the head as well, instead of just the sides, but otherwise, I highly recommend it.