Product review (4 stars): Follow directions carefully and should work well
After paying attention to other reviews, I read the instruction manual carefully before getting started.  When you are using the flexible rods and the duct cleaner, be sure to have that cleaning attachment clamped on extra tight with the included Allen bolt (little wrench also included) - you do NOT want to lose that in your duct.  Also, keep going clockwise with your drill (or by hand) or you will need a pro to come out and retrieve your kit (that didn't happen to me).  The cleaning rods barely fit into my 3/8" drill, so I'm guessing a 1/2" drill would be ideal for this kit.

I would also recommend having plenty of duct tape on hand so that you can tape the suction / cleaning attachment to the dryer vent - I removed the attachment several times during the cleaning because I had handfuls of lint that came down and my Shop Vac was getting clogged, so I had to manually remove quite a bit of the lint that this cleaning system dislodged.  When I started the job, I found that my vent made about a 90 degree turn before heading into my attic / roof area and the rods weren't quite flexible enough for me to feel comfortable using them from the laundry room end; however, I was able to go into my attic and detach the vent couplings up there then use the 4 coupled rods just fine.

At the end of the job, I had removed a significantly-hazardous amount of lint, then confirmed the job was complete by using the Shop Vac to blow air from the laundry room vent to the attic area - a strong flow of air was coming out with minimal lint particles (not the huge chunks I'd removed).  Again, used more duct tape to secure the vent attachments in the attic (which had been secured with duct tape when the house was built 20 years ago).

Overall, great product but subtracting a star due to the rod flexibility issue and that they should describe the need for a 1/2" drill rather than a 3/8" drill.