Product review (4 stars): Excellent Product - difficult to install.
Rated 4 stars because it was difficult to install.  There should be a template for where to place the screws.  There is no way to measure it accurately.  Once we got it in, it works WONDERFULLY.  Quiet on all but the highest speed (430CFM).  On the lowest speed, you might forget that it is on b/c it is so quiet.  We have it vented horizontally outside.  Excellent at removing steam and strong odors from cooking.