Product review (5 stars): It gets the job done... Easily!!!
This did a much better job than I could have imagined, and it was very easy.  It took me about 20 minutes to clean a 10 foot long dryer exhaust from opening box to clean up.  I got a HUGE pile of old lint out.  I was worried about the brush head because it looks like it doesn't have many bristles, but it is actually a smart design.  It works like a drill head to keep the lint behind the brush so that it comes out when you pull the brush out.  Just be sure to keep the brush spinning when you pull it out.  Now there is a strong flow of air and the clothes are drying quicker.