Bests & Worsts Reviews from Amazon

I just returned this item and amazon took $12 off for restocking fee. So I decided to write a review now to share my experience. The unit is small, which is good because I could put it on a table. One small thing that annoyed me was that the unit actually moved little by little when it was on because it was vibrating. So I had to put it on a more rugged surface to keep it from moving. The purifier worked perfectly fine for the first several days. It produced a humming sound, and it wasn't loud. I could definitely have it turned on while reading without being distracted. The high setting was quite noisy, but still it was within reasonable range of noise. Bottom line: if it were like that all the time, I would've kept it. Unfortunately, after several days, the unit became extremely noisy and produced a noise like popping popcorn in a microwave, even when I set it only on low. Then the noise became intolerable and I decided to return the item. Perhaps it was because I got a defective unit or what, I don't know. But before buying it, I read some reviews on amazon indicating that the unit is indeed very noisy. Some reviews, however, suggested otherwise, that the product is excellent. Given the mixed reviews, probably the risk of getting a very noisy purifier like mine is not extremely small. Hope this is helpful.