Product review (5 stars): I hate noise and I'm still happy
I installed it with 8" rigid duct, which was a nuisance because the parts are harder to find, but I wanted to minimise the noise in my ill-conceived open-plan kitchen.  That seems to have worked out really well.  The low setting is sufficient for a couple of pots on simmer (maybe boil if it's not smelly food) and isn't a disturbance to the television in the adjacent room.  Full power deals with plenty of oily/smelly food and you still don't have to shout to be heard.  I've met plenty of hoods that make a lot more noise for far less work.  Some of them could have been installed badly, but this unit has the low, quiet setting that makes effective use of a good installation.