I LOVE this thing! You wouldn't think something so tiny would have such a large effect, but it does! This thing is going on my list of best Christmas presents EVER! I'm a smoker with 3 cats and 1 dog (and I'm allergic to cats, but that's a longer story). Because of these things, I was on 2 types of allergy medicine and 1 sinus medicine that I had to take every day. Since I've plugged in the air freshener I don't have to take it anymore. It takes, I'd say, 90% of the hair and dander from the air. You can use it with or without fragrance, which really appeals to me because I'm allergic to most fragrances. Also, while you can purchase their expensive fragrance, you can purchase your favorite smelling hand sanitizer and use as much or as little as you want. When I use fragrance I merely put in a couple drops. My friend who bought it for me and who also has one, uses two or three squirts, but he's not as sensitive to smells as I am. Plus, (and this might sound a little girly, but it is what it is) the blue light is really pretty. The only reason this gets a 9 instead of a 10 is because the cat hair is a little difficult to clean out. And a warning to cat owners, one of my cats is insistent that I got it just so he could dump it over. Although this brings up another good point, he's knocked it over half a dozen times, with water completely filling the top portion and it still works wonderfully! It has an emergency cut off switch on the plug, I'm guessing, for just such occasions. I want one for every room in the house!