Product review (5 stars): Set it and Forget it
Best price I could find, and it seems to perform just as advertised.  It's difficult to rate something you notice so infrequently as a humidifier filter, but then again, isn't that the point?  I want to throw this thing in there and forget about it, and that's exactly what I was able to do with this product.  We use these filters in our humidifier in the winter with water to temper the dry air, and without water in the summer to provide some white noise at night.  Either way, these filters have proven to hold up very well with no maintenance.