A recirculating hood that cleaned the air of grease and odor to the level of the fresh replacement air resulting from use of an exhaust hood would be very large and likely fairly expensive to replace filters for. It would require a series of mechanical filters for different size ranges of particles, as well as charcoal filters for odor. The stack of filters would require a blower capable of the desired flow rate in the presence of a significant pressure drop. This would be noisier than a similar flow rated exhaust blower. Such a system's size would only be justified in some context where exhausting cooking effluent was prohibited. I am unaware of any units sold for residential purposes that would meet my sniff test, but there may be some somewhere. A search on this forum might yield a link to a thread I recall where someone had found a unit that met his sniff test. There could also be commercial versions available. On the plus side, recirculating systems would not need make-up air. kas

One big difference I have found in the price of hoods is the type of stainless they are made from. A Best hood is 403 stainless and the Vent a hood is 304 I believe. Best makes a "marine grade" stainless hood in the "WP" series out of 316 which is the best and it costs twice as much as the "KA" series. If you live in a coastal area with salt air you WILL get rust spots on a 403 stainless hood. You can polish out the spots and coat the metal to help this out but the finish will not look nearly as good as a 316 hood.

It's a universal recommendation that the hood be at least 6" wider than the surface it covers. And as deep as you can manage. It has nothing to do with the fuel used to heat the food. It has to do with the fact that smoke, steam, smells, and aerosolized grease particles rise upwards and outwards. That's physics. A smaller hood can't capture all of those yucks. Stronger fans can't compensate for a lack of capture area either. It's more important to have a good capture area than a strong fan.

Most people agree that the Vent-a-Hood (VAH) is a very good brand. The complaint people have against VAH is not how well the hood functions, but what it is like to clean. Taking down the assembly which consists of several parts is not as easy as just pulling down a couple baffle filters and sticking them in the DW. And a VAH hood of 48" or 54" has 2 blowers I believe so more parts than a smaller hood. The squirrel cage of the VAH is even a little trickier to take off and clean. Make sure you have a store show you how to take apart the VAH for cleaning. Make sure they show you how to remove the squirrel cage for cleaning, and don't let them dismiss it and not show you. That will help you decide for yourself. Regarding the Best brand hoods, there are so many. Best has a large line of hoods with varying features. What you need to look for is a hood with baffle filters, not mesh. Mesh filters tend to get clogged with grease quickly which impairs their function. Baffle filters, while still needing to be cleaned, don't need to be cleaned as frequently and don't have their function impaired if they are not. Hoods with baffle filters cost more than ones with mesh filters, but it is worth it IMHO. Regarding noise level - a great deal of noise level is generated by the ductwork. If your duct from the hood to outside is too small in diameter, the hood will be noisier and less effective through no fault of its own. Typically hoods need an 8" or 10" diameter duct. You are looking for a hood at 48-54" size, and your duct size will need to accommodate that. The specs of the hoods will say which size duct is needed. Most of all, a "quiet" hood is a pipe dream unless you are doing a remote blower as Kaseki mentions. Any motor at head height pulling 600 cfms or more will be noisy, regardless. There are of course some that are noisier than others, but all will be noisy unless you install a remote blower which can be $$$, and difficult installation depending on your home setup. Other than that, the biggest difference in noise level will be attained by properly sizing your ductwork.