I have several and like them. I have them because I have a cat with a mold algery and it helps him, alot, mold doesn't like ions. It also helps pull smoke out of the air. And it will pick up some dust, it may look dirty but only picks up a fraction of the dust going through it for this you are much better off with a hepa media filter. The problem with the ionic filters is they through out lots of ions, which are not necessorly good for you. Now with that being said I havent found any really good proof that they are bad. So my advise would be look at what you need to clean in the air and if it is smoke or you want to keep the mold down in a damp room go for it. If you don't have a problem with this why ionise the air.