I used to use it in quite a few beers (15-20). I didn't notice much of am increase in clarity, but I did notice a positive reaction to my allergy to beer (and gluten). I felt like it stripped out too much flavor/aroma to make it worthwhile.
In case anyone is wondering, I am allergic to beer in the sense that 3+ full beers do not allow me to breathe out of my nose, like a stuffed up feeling. I liked that I could drink more beer without having any nose problems, but there was just something missing from the beers using Clarity Ferm.