nice and quiet and has a sleek design. I wish the USB came with the cube plug-in. I seem to always be stealing one from somewhere in the house and it would be nice to have one supplied with this product. It is hard to tell if ' clean in the air or not. I mean how do you know? But I suppose I will know if the filter eventually has debris. On that note. It would be nice to know how often to exchange the filter. The instruction manual did not give that detail.