The FAQ list the specs for hoods based on BTUs so you can get a better estimate there.

I have the Zephyr Typhoon and it's great. Even on the second setting it works when I grill meats! And it isn't horribly noisy, we can still watch TV (I have a great room style open kitchen) but we do have to turn it up a bit. It's less noisy than the dishwasher!

Our Z Hurricane was just installed yesterday. I chose it for the 3 speed fan and the 2 setting halogen lights. My last hood had terrible lights and a weak draft, so this one is a huge improvement. The cooktop isn't in yet, so I don't know how well it works while cooking. The highest fan setting is loud, but what you would expect from a powerful fan. I like the idea of a timer setting so the hood can be left on for set amount of time.

My only concern is that there is no filter covering the intake vents, and I wonder what a year or two of stir frying will do to the underside of the hood. The promotional literature says the hood "liquifies" airborne oil, but I have no idea what that means. This hood sticks out further than my previous one, so I've hit my forehead on it while reaching to the cabinet above. However I think I can be trained not to do this again.

We have the Hurricane. It's pretty noisy, IMO, and does not remove all cooking odors. If we fry something, we can smell it the next day. The noise is the same on all three speeds. It is vented directly through the wall behind it to the outside. It does seem to work as it's supposed to, and it moves a lot of air (695 cfm), really kind of overkill for our small kitchen (~200 sf?) and low-end gas range.

We've only had it for a week or so, so no long-term experience.

We have had the Hurricane installed since November and I love it - the lights are great, and the fan although is a little noisy, it works great - much quieter than the previous cheapo Allure. I grill meats a few times a week and have no problems with lingering smells or smoke.