Product review (5 stars): This thing is great.  Does the job well, not too pricey.
My dryer run is 34'.  I bought 3 kits.  It was actually cheaper to buy 3 kits, than to buy extensions to reach 34'.  The length worked out just about perfect as the poles aren't always geometry straight when they're going thru the vent, so I needed every single extension rod (36' total) to clean a 34' duct.  As others have stated:  NEVER run the drill in reverse (counter clockwise), you will unscrew the connections and you will inaccessibly strand your rods and brush inside the vent.  I duct taped each extension connection point, but I don't think that's really necessary.  It will buy you a couple seconds of insurance in case you accidentally reverse the drill.  Probably smarter to just duct tape the fwd/rev button on your drill in the fwd position.  I put my drill on low speed which is plenty of rotation, in my opinion.  I tried it on fast speed and I seemed to have a harder time unscrewing the connections when finished.  I think fast speed way overtightens the connection points.  I cleaned from the vent exit point, going "upstream" a foot or two at a time, then reversing (not reversing the drill, that's always fwd/clockwise, but pulling out the brush to clear lint), while the dryer was running on 'no heat' setting.  That way the airflow pushes out what you loosen up, a little bit at a time.  If your vent is already plugged, this method probably isn't the best way to go.  All I can say is I got A LOT more lint out than I expected.  Two regular size Target bags, filled to the handles, full of lint and hair too.  That was one of the biggest surprises, how much hair came out.  Gross.  Can comfortably say that the dryer vent is completely clean now and done for half the price of a professional cleaning after a single use.  Plan on using it again every year.  If I had any critique it's the time it take to screw/unscrew each connection.  Not a big deal if you have a 10' run, but mine is a very long dryer vent run.  However, some kind of quick-connect would probably drive the price up too much.