Kitchen exhaust hoods can be very decorative, but don’t forget to have them sized right. It is recommended that they pull at least 100 cfm of air, but 150 to 300 cfm is better. Oversizing the exhaust fan is not a good idea, as it will pull unconditioned air into the home while it is exhausting air to the outside.
It should be exhausted to the outside, not the attic. The duct should have as few bends as possible, and be smooth sided; you don’t want grease to become trapped inside the duct and possibly cause a fire at some point in the future.
Quiet fans are always better; sound is measured in Sones or Decibels. A Sone rating of 2 (or 50 in decibels), is comparable to a dishwasher running; a sone rating of 8 (80 decibels) is similar to a gas lawn mower.
The fun part is picking the style of exhaust hood that will complement your kitchen. One range hood for that dramatic appeal is the free-hanging ceiling mount type. These are usually installed over an island, or over a peninsula.
Another style is wall mounted, but exposed. They often have a decorative chimney.
The under cabinet mount is very common; it can be ducted up through the cabinets and attic to the outside.
A fourth type is downdraft ventilation; usually found in kitchen island or peninsula applications. The fumes are drawn downwards under the floor and out, similar to a clothes dryer exhaust. Downdraft systems are less efficient because they have to fight the natural upwards flow of air, but they have the advantage of not blocking the view.