Some people recommend these ionizers that are supposed to knock down dust, bacteria, mold, etc. out of the air. They leave the rainy day fresh air smell in the house. I think they have some merit and would help people with asthma and I would like to have one but it probably isn't the first place I would spend $600. I'd go for the electronic air cleaner or hepa filter first. Most places let you try the ionizers out for a week or so and I did that. They say that these ionizers will knock down for dust for a while till the air cleans up. This may be true but I'm not sure I saw a reduction after a week. People with sinus trouble think they are great and that would be enough reason for me to get one. They help keep bacteria out of the air which helps with colds, etc.
Contact a local seller and try one out. You have nothing to lose. Post back with the results. You will get used to the fresh air smell and they recomend that you turn them down so you just notice it for a few seconds as you walk into the house. Don't buy based on smell of the air but look for effects on your families sinuses and respiratory functions as well as the dust. See if someone will let you try it for a month or maybe rent it for a month to see if it helps.(think I'll stop by and see if I can get a month trial) And like anything with a fan, it will make a little noise which may be noticable at night when all is quiet and you have to have your doors open unless you put it close to a furnace return. Lastly maybe others have some experiences with these and will chime in.