I think Joe is spoiling us with 2 DVDs (nearly 3 hours of video) and a book. He demonstrates and comments on many different kinds of shots that come up all the time. I learned to see certain difficult shots in a different way that made them seem much easier. I'm not even sure that it's the Aiming By The Numbers system specifically that did it for me, though seeing shots in a new way always gives a new perspective. I just found that as he set up the shots (and shot them in) that his comments were often insightful and taught me things that didn't occur to me. Kinda like if you got to spend time practicing with a professional... He might not teach you anything earth shattering that you didn't already know, but he might drop one or two pieces of insight that make certain things seem much easier. That's how it felt to me watching these videos.
By the way, but if you have not seen Joe's "Racking Secrets" (2 DVDs) -- it's the greatest thing since sliced bread. Thanks to Joe, when I play nine ball now I fully expect to make the corner ball on the break 100% of the time, whether it's a perfect rack or has gaps. That's very empowering. I'm not selling them, just passing on the rave reviews.