I've seen both the smaller and larger version of the Ionic Pro air purifiers and have to say they are good but certainly not great. I've seen dust go in one side and right out the other but it does trap it sooner or later when it passes through again. Even the large one is only good for small rooms and after a while the pleasant ionized air smell becomes a little annoying. It is useless on cigarette smoke and some litter box smells but even though it is not a great machine I would have to say it still is Good. But both version of this machine are very over priced and I would not recommend spending money on these until they come down. Yes, you do save on filter costs but that is sort of compairing apples & oranges. I still give both versions a 3.5 star but the price brings my rating down to just a 3 star. I also recommend getting something to cover the LED light on the machine because it's super bright and can be annoying when you're trying to sleep.