I have two of these diffusers, one at home and one in my office and they work great!. I have six of these in my home, use everyday and have never had a problem with any of these units. Have bought for others as gifts and the same holds true for others as I am describing so they tell me. I especially like how quiet it is as I use one of my blends for a restful sleep which works perfectly. Easy to use right out of the box, simply fill water to the maximum line, put a few drops of (high quality) oil in the reservoir, press the button and it automatically turns off in about 4 hours. I clean regularly (half & half distilled vinegar and water for 2 hours) when the vapor is not as strong as in the beginning.