Product review (4 stars): Only had this for few days. Heres my opinion so far...
For now I can only give it 3 stars, as I've only had the product  I'm using it in for few days. From what I see so far, there isn't a bad odor from this product. I'm not seeing any build up or smells.  It does leave the water in humidifier sudsy a little. Goes away once settled. I'll write an updated review, once I've had it for a few weeks. Quick shipping.