Billy Goat is a bigger ski. It is stiffer, more demanding to ski, and more powerful. It is still a very quick ski, you just need to know how to ski. The s7 does not require someone knowing how to ski, which is they beauty and annoyance of it. I think the best way to put it is that Rossi has come out with the Super7, and now the Squad7, which are more powerful chargier versions of the s7, ON3P has not come out with a super Goat, just a bigger size.