I purchased the Alen BreatheSmart 45i over a week now and it's great! I knew my air quality here in Los Angeles was always a problem, but this device assures me I will have the best air quality possible with its automatic air quality setting. It is also impressive to see how it handles cooking odors. The led indicators for air quality are a great feature. I have recommended to my Office facilities manager that we invest in this air purifier at work on a larger scale.