Product review (3 stars): Works as described, but beware.
Depending on your house, it says fill every 1-2 days.  Wrong, I was filling every 3-4 times per day.  Works as described so I cant say its bad, just beware it is also huge compared to the smaller vents i swapped it out with.  The amount of effort required to refill every couple hours, I bought a humidifier instead.