Product review (4 stars): quick review: it works as advertised (very pleased)
I bought this a year ago and it sat in a pile on my workbench waiting to be used.  As the guilt mounted about all of the dust in the vent conduit... luckily my dryer died!  In replacing the new dryer yesterday I felt compelled to use this.  Took 5 minutes to open the box and assemble the unit.  90% intuitive and I only doublechecked the manual for attaching the plastic brush.

Funny that peope say the instructions tell you to only connect 2/3 of the extension first... duh!  That 12' is LONG and if you hook it all up at once and use the drill you're likely to cause the line to double over itself and break.  Kind of obvious to me so after doing it in 2 steps... it worked AWESOME!!!  wow was there a lot of dust in my 20' run!  Did it from the inside and pulled out enough lint to fill a shoebox.  Went in from the outside and achieved the same result.  This is after 5  years of not cleaning it out.  Am very pleased.

The best part is once I started the new dryer it started 'snowing' lint outside.  Seriously it blew a TON of lint out!!! Very satisfied.

I already owned a drill with a clutch.  I think that's a requirement or you'd better be very careful when using a slow-speed drill without a clutch.

My shopvac tube was too small.  That's a bummer.  They should include a plastic adapter for smaller hose sizes than a shop vac (like used with a standard vacuum.  That's the reason I bumped it to 4 stars.

Bottom line:  Does the job.  Be sure to have a drill with a clutch.  Takes 15 minutes total.  I'm very very satisfied.  Hopefully in the future they'll include a small vacuum to shopvac adapter.

-zb