Product review (5 stars): Excellent product - Great installation flexibility/Ducted or Ductless
Changing out the kitchen appliances to stainless and the Broan QS230SS replaced a 15-year old Broan builder-grade vent hood.  What an improvement!  The product looks and works great.

It took approximately 1 1/2 hours for me to install.  Since I was replacing a Broan vent hood, I was able to use the mounting screws which were already in place under the cabinets.  This was nice as I was doing the installation by myself.

The unit is quiet, even on the highest speed, especially compared to our previous vent hood.  When I tested the unit, there was a slight rattling noise coming from the damper when run on the highest speed.  This rattling noise went away once the duct was attached and the filters installed.

I elected to use high quality dimmable LED bulbs instead of the recommended 50W halogen bulbs.  Utilitech PAR20 9W (50W equivalent) bulbs work great.  There is no flickering and the bulbs are instant on.  One review that states one cannot use the lowest light setting without first turning the light on a higher setting.  That must be a defect in that user's unit.  Mine works perfectly.  Several reviewers comment on the heat sensor turning the fan on the high setting when it detects a certain level of heat that the user believes is not present.  This could be caused by the use of halogen bulbs which produce a good amount of heat which is another reason to use LED bulbs.  Remember the LED bulbs must be dimmable and sometimes lower price/quality bulbs will not work properly.  The LED bulbs will produce less heat, last longer and use less electricity than comparable halogen bulbs.

The unit allows for a ducted or ductless installation.  For those reviews which state the unit blows smoke back into the room, in all likelihood they did not correctly install the baffle for a ducted installation per the instructions.

Just follow the instructions carefully and you should not have a problem.