Product review (5 stars): Excellent product
I installed this hood in February and wanted to use it for a while before giving a review.  I am a remodeling contractor and I have installed quite a few high cfm range hoods costing $800-$1000.  I am very happy with this product and have just purchased another to use in a customer's kitchen.  When the duct is installed properly the fan is as quiet as most, and while I do not know that it actually produces 800 cfm I do know that it is powerful.  The only drawback is the lighting that, while adequate, is kind of weak.  All of the more expensive hoods have far better lighting with settings from low to high.  Still for the price this hood is fantastic.
I do have to stress the importance of proper ducting.  Too small of a pipe, too many elbows, or too long of a run decrease performance and increase the turbulence and therefore the noise that this or any fan produces.  I would have to think that most negative reviews are a result of improper ducting.