Product review (5 stars): This thing works great
I was a bit worried about other reviewers' tales of woe of the device breaking off inside the vent. Mine worked fine. We have a long run, about 18 feet of pipe to the outside, with 3 elbows. Slowly feeding the sweep in from the outside using a cordless drill, while running a vacuum (just a regular one, duct-taped to the adapter provided), all went great, other than the vacuum getting plugged at one point from the large amount of lint loosened. The device reached most of the way through our run, with the last few feet being cleared by going from the inside.

Before cleaning the vent: our newish dryer was taking 3-4 runs to dry a large load. Washing and drying the clothes took constant attention and much of the weekend.

After cleaning: one run now fully dries all but the most layered clothes (e.g., hoodies' hoods).

Best money and time I've spent in a good long while.