quality with cx heads can be spotty, but as a rule they are good heads in general. As to the f 15 specifically I have not tried or tested them. I will say that's a lot of cutting surface so penetration will probably be less than most heads of similar diameter. On the other hand you get a lot more tissue damage compared to heads of equal diameters. My overall opinion is it's more of a marketing gimmick than any real advantage, but I am sure they will kill critters just fine, provided you have a fairly heavy setup.