Product review (5 stars): Good tool. Personally tested.
The previous owners of the house appear to have never cleaned the dryer vent, so the laundry was still damp after 40-50 min. cycles. This kit was just what doctor ordered. I did three inside-out runs, filling two shop vac buckets-full of crap. Then I did two runs form the outside to inside, to make sure nothing was missed. Result: when I connected the dryer and turned it on, I could feel the hot air coming out of the vent and the pressure was pretty good.
I'd say 38 bucks and a couple of hours of work is a pretty good savings, considering that the contractors would charge approx. $150-$200 for the job.