Product review (5 stars): Easy and effective tool
This product is well designed and easy to use.  The directions are helpful and show exactly how to properly use this to clean your dryer vents.  A DVD is also included, but the written directions were clear enough that I did not use it.

I have a long run of about 25 feet with several 90 degree connections along the way.  I was concerned that the brush or extensions would become jammed - this did not happen.  I was careful to make sure that the extensions were properly connected to one another and that a small amount of duct tape was used at each join as instructed.  It seems important to run the drill in a clockwise fashion to minimize the risk of disconnection the joins of the extensions - the directions are rather clear on this point.  My 14.4 cordless drill had plenty of power to complete the job and was easier to use than a corded drill. I also used a shop vac and the included adapter to catch lint and dust on the non-auger end of the vent tubing.

I cleaned my entire run in about 15 minutes of total work.  For what you get the price may be a bit high, but I'm sure that the overall cost to do this yourself over several uses would be much less costly than hiring a professional to do the same.