Hey man! They're really groovy. All those pretty sparking glittering lights - and that peace everywhere. Awsome!
Seriously though, they can produce ozone that smells a bit like the seashore. That can increase cellular oxidisation and increase in free radicals (bad for you). Have a Google around and see what you think. I personally would not recommend them save your money for a nice pampering day at the beauticians/hairdresser/sauna.
One of the best adverts I have seen is one involving an ioniser. A large glass canister is filled with tobacco smoke, the ioniser was turned on and within literally seconds the smoke had disappeared. I have two ironisers, one of which is in the car...you notice a coolness in the air. My bedside device is not so successful and hardly notice its prescence.
Oh - not all that helpful then. Just taken my baby to the GP and she recommended one for his breathing. Also a friend bought one and that night she noticed that everyone stopped snoring! - her husband and 2 sons!! so worth it just for that!
Perhaps I would have got a different response if I had put this in the body and soul section?!? I expect that different types of people read each topic section??