Product review (5 stars): You get what you pay for and the QS3 is worth it!
Looked at the QS1, QS2, and QS3 models.  Picked the QS3 for all the extras - 3 light levels, squirrel cage fan, and auto speed up in case of excess heat.  Controls are all touch switches.  Extremely quiet in low speed.  Installed straight through the wall - tail piece is provided but needed extra 3" section of duct pipe ($3.00 at Menards) for 6" wood wall structure.  Bought outside vent opening at Menards for $15.00.  Went with halogen bulbs (daylight) for great glow in low light setting.  Looked at LED bulbs - decided against because would have stuck out below recessed light opening.  Easy directions for someone mechanically inclined.  Have a buddy help hold it up when you mount it under cabinet.  Amazon got it here on time as usual - Bravo!