Product review (5 stars): Incredible well designed and working filter... Glad I gave them a try...
I usually don't write reviews however I took the chance of buying these filters despite the lower star rating.  After using them, I feel the few reviews that are here that are negative don't really do the product justice.  I am new to using a humidifier in the house but I currently have the Hone ywell Germ Free Cool Mist humidifier.  When I bought the humidifier I decided to get an Acu Rite electronic humidity monitor to tell me the humidity in the room.  I can say that the stock filters lasted about 4 weeks or so running the unit every night for 8 hours.  All of a sudden, when the temperature dropped and the heat started running, the humidifier was not able to keep up.  Figuring that the filter was done, I checked the unit and the filter was dry.  I decided to give these a try as if they last an entire season, then they pay for themselves.  I can tell you that the humidifier is working incredibly well.  In fact, it actually seems to be releasing humidity at a faster rate since I now have to fill the tank every night.  With the paper filters, I might of had to fill the humidifier every three days.  Also, the rate at which the humidity is rising is also faster as I can see this by the humidity monitor that I mentioned.  I don't have experience cleaning these yet however I can tell you that they appear durable.  When you first wet the filter, make sure to turn it over a few times, to allow the water to seep into the filter.  Be sure to buy an electronic humidity monitor (they're like $10) as it will help you determine if it is doing the job.