Product review (5 stars): Works like a champ!
This review is after installing and running about 5-10 loads of washes through it.  So far so good.  The install was fairly easy, you do need 2 additional 4" dryer duct clamps.  The unit rapidly turns on and off automatically as it should.  I can't tell whether it's shortening the drying times yet, but it definitely blows the lint down the line and out the exit way vary competently.

The reason for the purchase was that I have a rather long run for the dryer vent pipe with several bends and curves in it.  The dryer failed and I had to have a tech come out and fix it after I cleaned out the entire vent pipe and that didn't fix the problem.  When the tech opened the dryer up I was surprised by all the lint that was caked inside the dryer itself.  I was thinking, Holy Cow Batman, can you say lint fire!  They say not to run your washer and dryer when your not at home to tend them--now I understand why.

I feel much better now that the dryer will be venting the lint much more efficiently.