Hi,
Which range do you have? I think as long as it isn't a WOLF, Dacor etc you should be fine with 700cfm & under.

I got a Zephyr Tempest 1 & per my contractor it is quality hood! In our last house we also had a Zephyr (different model though) and it worked really, really good--cleared out all our coffee roasting smells not a problem (thus the reason I'm getting another Zephyr).

My contractor just installed our tempest & haven't used it yet but it looks really nice, and love the baffle vents on the underside (looks a little more professional IMO).
Here is a pic of what we got

Check out Kobe hoods - lots of good reviews on them. Unless you have a grill on your cooktop, you'll most likely be fine with 600 CFMs regardless of what brand of range you have.

Nikki

First step in range hoods is - what range, cook top you are installing - size/burners/grill/griddle configuration

2nd - What type of cooking do you typically do - Grills & Woks will require greater CFM's than simple sautes

3rd - Is said range/cooktop on exterior wall & have the capacity to vent straight out? - no plumbing, electric, framing, etc that would make that impossible.

4th - What style are you going for

Once that has been answered you will get more information as to what is available

Normally you select a range hood based on the BTUs of the booktop or range it's over, and the width of the same.

The size of your kitchen and the way the range hood is ducted matter, too - as done the type of cooking you normally do, but duidn't so much to me (I'm not a professional chef, I just like to cook fun family meals).

The general guideline our appliance guru recommended was total BTUs / 100 = CFMs.

We have a 36" Kitchenaid cooktop with 51,000 total BTUs (18k, 6k, 7k, 10k, 10k). Our guideline was a minimum CFM of 51,000/100 or 510. We went with a Zephyr Cyclone @ 650 CFMs. I would have gone a bit higher if I had done much woking, sauteeing, etc.

Ours vents straight out, not up and no bends.

We have no issues with smells lingering. You can really tell the hood is on when we have the window open. :) After years and years with an OTR microwave, I can REALLY tell a huge difference. No "ring around the ceiling," no greasy cabinets or lights, etc.

Are you replacing an existing range hood? If so, you should find out what size ducting you have already. We had 6" ducting so we bought a range hood which worked with 6" ducting. If you buy a range hood which requires 8" ducting, you will have to replace your ducting which could add to your overall cost. We bought a Kobe which works with 6" ducting.

Nikkipetey - there is a thread on the Appliances Forum about a Kobe hood selling at Costco right now. The hood goes up to 640 cfms, has baffle filters, can use a 6" duct (if that's what you have), comes with a 2 year warranty from Kobe, plus you have the Costco return policy. You didn't say what width is your range. The one at Costco comes in 30" and 36" sizes. I'll link the thread, and there is a link within the thread to the Brillia hood at Costco.

Here is a link that might be useful: Thread about Brillia Hood by Kobe at Costco

I have a 600CFM fan in my Viking hood. I really have absolutely no need for anything larger 600 is PLENTY of power for me. It clears the kitchen out extremely quickly and I can feel cool air coming in from the other rooms. While I like the way my hood looks, it is too loud, and had a couple issues which have been taking forever to get fixed. I wouldn't recommend a Viking hood.

How many CFMs you need is heavily dependent on the size, length, and path of the ductwork run to the outdoors. Longer, twistier ductwork runs need more forceful fans.