So first of all, I'd recommend forking out the less than $20 to get this PDF QB catalogue emailed to you. It's obvious he put tons of work and time into this. Last year when someone first mentioned him to me on reference to this catalogue, my reaction was: "who the hell is Cian Fahey?!"
Well, in short, he's good at what he does... having worked at Footballoutsiders for a while before going out on his own. But no matter what you think of his knowledge, what the catalogue primarily accomplishe