Product review (5 stars): Ditto....on all counts
Honestly, I can't add much more than what you've already read, but I will... This tool just plain works as advertised.  I had to clean approx 40' of vertical/horizontal dryer duct and it did an excellent job.  I bought the extension pack but didn't use it because it was working so well with the included extensions I didn't want to press my luck.  I needed to inspect the horizontal run through the attic and I was hoping not to have to climb up there.  But to be safe I got in the attic and inspected the ductwork just to be sure.  It was as clean as the dryer duct in the included DVD instructional video.  This tool costs just $30+ and it had to save me hours and certainly $ on this project.  I don't own a cordless drill, so it got a full-powered corded drill instead.  No problem...just exercise a little caution when running it the full length.