S.W.
We have the IQ Air, supposedly the best and I can't disagree. It's made in Switzerland and used widely in Hong Kong and China. We actually live in Hong Kong so I can tell you it really works great! It has three layers of filters but ours has been running 24/7 for over a year and they still haven't needed to be replaced. It comes in two different sizes and has 6 settings, includes remote, and it's on wheels. Definately worth the cost if you want the best.