It's not the reprints that bother me, it's the large number of updates which make this thread necessary that makes the Adventurer's Guide a book I will never purchase. It's hard enough running a game when players at your table are referencing third, fourth, and fifth edition core rules and I as GM have sixth edition. Most notable was a confusing disagreement we had over immunity to baleful polymorph. I eventually got to the bottom of the confusion by referring to the errata document.
Without a cross reference document that is much easier to read than the standard errata document purchasing this book invites a slew of confusion for me as GM. It's hard to have confidence in a book that I will have to constantly cross reference online when looking up player choices.