This machine is awesome! It is by far the quietest air filter ! It is by far the quietest air filter I have used. I use the auto feature and have seen it in action. The manual said it will be blue for good air quality, orange for medium and red for bad. I was cooking a steak and it got extremely smokey; the unit was in the next room and when I walked in it had changed to red and was turned all the way up. I thought this was so cool! You could not see smoke in that room but it sensed it and cleaned it up. Within about 45 minutes it was back to blue-good air quality. I have a dog who doesn't like noisy, unfamiliar things and she sniffed this once and has ignored it ever since. 
Taking the air filter in and out is extremely easy, and using the unit is also easy. It is not an eyesore and not loud. I am happy with it.