For the past few years, I had purchased the OBR at Barnes & Noble, here in my town. They carry the edition that is published by The Sporting News.
This year I purchased an edition that is published by Triumph books, which I ordered from Gerry Davis Sports.
http://www.gerrydavis.com/
I think that the price is about the same, and I like the Triumph books version better, because it includes approved rulings, case plays, and clarifications/interpretations. I would highly recommend it.