Product review (5 stars): This thing is GREAT!
This thing is GREAT!  I have about a 24 foot dryer exhaust pipe running between floors in my house.  I bought this and 12 ft of extension.  I carefully read some of the reviews and made sure I slowly inserted the fiberglass poles, after insuring they were tight and wrapped with duct tape.  You do NOT want to reverse direction of your drill when using this.  I can not imagine having to retrieve a pole that has disconnected and is inside the pipe.  The only problem I had was starting from outside the house and running the dryer so it would blow lint out as I went. I found since mine was so clogged I actually created a damn of lint near the dryer inside the vent. This was where the vent pipe took a turn up.  However, after determining the cause I went into the house and used the supplied cutter attachment and slowly proceeded towards the outside of the house.  I could feel the clog and soon the cutter had made its way thru the blockage.  Using a leaf blower I inserted it into the vent from the interior and two softball size lint balls blew out.  System cleared!!!  All is good.  Just be sure to take your time and do not reverse your drill.