I have had a Venta LW15 for a long time, and like it. I have gone through many humidifiers, and the LW15 is the only one that has lasted more than five years and does not require filters. It is expensive, even with cleaning>

It does require regular cleaning, though -- that can be a pain. It pulled minimal power, too.

I have switched to a whole house humidifier this year and I really like not having to change water every day. I am not sure how it will work in the long term.