Product review (4 stars): Works fine
Works great on my short ducts.  The long brush was not terribly helpful on my dryer, but maybe if I had the top filter kind instead of the inside the door it would have been more useful.  I should also say that they reccomend working from outside the house towards the inside.  I did mine the other way, and discovered why.  When it gets pushed through the wall, the flap that prevents rodents and birds from getting in trapped the brush.  I had to disconnect from the drill and push it through, but it all owrked out and I saved the $200 that my neighbors were being charged for a pro to come out.