Product review (3 stars): Works, but brush attachment is fragile
I used this to clean my 22 foot vent run.  While it does work, the instructions to set the drill clutch slip point could use some work.  I set it as described, but still stripped out the vent brush, during the first use.  The brush hub is plastic and the flexible rod that screws into it is too small, so the threads in the plastic strip easily.  This would be an easily fixed design error, and I guess I'll have to fix the stripped brush on my own, I just don't think I should have to.  I tried to contact Gardus to get a replacement, but got no response.  So I suspect that this is a common occurrence and is too expensive for them to either correct the brush design or give replacements for failed parts.  The parts in the box are useful for cleaning both the vent and the dryer.  Other than the brush being easily damaged, it is a well thought out kit.
Update...a new brush showed up on my door step today.  Gardus came thru with a replacement part.

5/30/15: Used the system again today, and it worked as advertised. I just need to remember that the brush hub is plastic so I set the drill clutch on 1 (the lowest setting). I may go to the hardware store and get a threaded insert to beef up the brush.