Bests & Worsts Reviews from Amazon

I read quite a lot of reviews about this particular air purifier, and while they were all glowing and guided me to purchase one of these I was very disappointed with the one that I received (which I returned for a refund). This doesn't seem like a common complaint so I'm likely the victim of a damaged unit (perhaps during shipping), but the when the fan was on high it was obnoxiously loud and vibrated so hard that it scooted across the floor. I had the unit in my daughters upstairs room and we could hear the vibrations downstairs with music playing and loud talking. I suspect that the fan/motor may have come out of alignment at some point during the shipping process, or perhaps it was just a defective product. Whatever the case, this thing was twice as loud as our Honewell 50250 which has a reputation for being among the loudest air purifiers. Also, the air quality sensor seems sub par at the factory setting. I purposely dropped some dust around the unit to see if it would pick up anything and it never did. I also huffed directly into the sensor, beer breath and all, to see if I could active it. It wasn't until I adjusted to use the highest sensitivity settings that the unit finally started (quickly) picking up changes in air quality, and from that point on it had no issue switching gears when air quality degraded (like when my wife burns bacon every morning). Not a huge deal, but certainly something to be aware of. Finally, the air quality display light on the top is way too bright (illuminating nearby walls and ceilings) and can't be turned off. This seems to be common with most, if not all air purifiers, but one has to wonder what in the world these companies are thinking given that these things are expected to run 24/7 in bedrooms, particularly for allergy sufferers. Luckily this is easy to fix if you have a small book laying around (or duct tape), but still annoying, particularly since night lights affect quality of sleep. All that said, I'm strongly considering ordering another one and hoping that the first one that I got was just a fluke. I've spent weeks reading reviews and the test results of the Coway are very, very impressive. If not for the noise and vibration, I'd give it 4/5 stars.