Personally, I think beginners who want to learn rock rhythms should be introduced to AC/DC before the Black Label Society. AC/DC's stuff is much more popular and more fun to play, and the skills picked up from learning AC/DC songs can be applied to other songs and even other styles of music. You're better off learning Black Sabbath than learning the Black Label Society (in my opinion, BLS are just Sabbath with a worse singer and faster solos, anyway :p ), but if you're going to study them, it's probably best to do so after you've already got a handle on some Deep Purple or Kiss.