I have used an ultrasonic humidifier before and could not meet the humidification needs of the room. Although the ultrasonic humidifier seemed to have a large mist volume, it could only provide humidification for a small area nearby and it would wet my floor. I found this steam humidifier on Amazon and I purchased it. Its steam is not as obvious as ultrasonic, but you can feel your room being humidified. The warm steam makes it more comfortable to use in winter.
It seems to run for at least 10 hours before I need to refill the 10-liters of water (5 liters per tank). The two water tanks are very easy to lift out, by their well-designed and sturdy handles, and the legs on each tank make it very convenient and easy to refill them in my kitchen sink, since they stand up by themselves.
I love this humidifier, a lot, especially for its effectiveness and ease of use. And I really love the fact that it boils the water and produces actual steam, instead of just mist. The non-steam ('mist' only) humidifiers have always coated everything with fine dust. And they also put everything that is in the water into the air that you breathe, which would include not just the minerals but also all of the contaminants, such as any fluoride, chlorine, and insecticides (we have "farm run-off" chemicals in our water, for example), and any other chemicals, and any heavy metals, etc., that were in the water. Real steam is the only type of humidifier that I would ever consider.
Very satisfied with this product, I will recommend it to my friends!