Product review (5 stars): Seems to be a quality, brand name product at a good price.
Lots of reviews noting they got a cheaper, generic product.  This came in the Vornado packaging and the quality of the filters is the same if not better than what originally came with the unit.  Can't say enough about my Vornado humidifier.  I have personally come to believe replacing these annually is the best idea.  I use bleach a couple of times per winter season to stop mold and other microbe build up and I think the bleach greaks down the material over time.  It is not much of an annual investment to make sure everything is clean and functioning well.