My first thought was: "How is this different from Google Analytics?" I imagine that's the 800 lbs gorilla you're dealing with, right? So, it might be worthwhile to just throw that in my face right when I show up. Tell me why I should pay money for something I can already get for free.

(Note: I'm not saying your site isn't worth the money, just that I was unable to immediately determine what differentiates you.)