Product review (4 stars): Does what it does well
This basically does what it's supposed to - saves space and allows you to move the dryer close (3-5") to the wall.  However, be sure to use plenty of HVAC tape on all the seams as they are just tack welded and crimped together.  I even went sofar as to use some tape inside the unit where the collar mates with the periscope section because it's more of a slip on connection.  Once at the correct height and all taped up, airflow will be quite good through it.  One thing of note is the collar that attaches to your dryer is a bit short.  Wasn't an issue for me, but if your dryer's exhaust is not protruding or flush with the rear, you will have to get a coupler which will defeat the purpose of this.  I also used a worm drive clamp on this for good measure.  For those worried about how this design will affect the overall length of their dryer exhaust run, it worked just fine for me in a 35' overall run w/ one 90.  I would have given this 5 stars if it were not for the prep time it took with HVAC tape to get this installed.