Product review (5 stars): You will need two people for this one!
The quality of the Zephyr AK2136A 850 CFM 36 Inch wide under-the-counter vent hood is obvious.  Once installed it is a beautiful addition to your kitchen.  It is powerful and has nice features like 5 minute and 10 minute shut off, as well as two settings for the halogen lights (full and night light).  And best of all is the 6 speed fan.  You probably don't need 850 CFM in daily use but it is nice to know when you smoke up your kitchen you can get rid of it quickly.  Again, once installed it is perfect.

I did say "once installed" for a reason - it is not the easiest installation.  It weighs about 45 lbs, and you have to hold it up perfectly centered and level before you can install the screws into the bottom of your cabinet.  You might find it easier if you first protect your cook top with say plywood or thick cardboard.  Then find some sturdy boxes and stack them up so when you place the hood on the top of them you have about 1/2 inch from the top of the hood to the bottom of the cabinet left to go.  I did this because I also had to get the power cord through the hole I made in the bottom of the cabinet at the same time (which isn't easy).  I found it best to first trace the top of the hood and then transfer it to a piece of cardboard (included in the box).  Make sure you also trace where the electrical wires will go through the bottom of the cabinet and of course the vent configuration you will be using.  I decided to stay with the 3 1/2 x 10 vent that was already there (which required a change on the top of the hood [see instructions]).  Also don't forget to open the electrical box in the hood to bring the green ground wire up with the black and white power wires.  You will find that it is rather short and you may need to either replace it with a longer wire or place your power outlet close to where the wires come through the bottom of the cabinet.  I put a 20 Amp GFCI outlet very near the power cord hole in the cabinet on the back wall.  Finally make sure your vent connections are sealed with aluminum HVAC tape.  The hood has a very powerful fan and it will test your vent ducts and any weak point in the connections.

Once installed you can relax and enjoy!