I find the BB to be useful as a "general across the board tool", but it is just one of the many things that goes into my buying or asking price. As a survey level document, it's not bad and has provided a lot of knowledge that I wouldn't otherwise have. Once you start getting specific or esoteric, you'd better know what you're looking at and have some additional "special knowledge". Do your own due-diligence or be prepared for the consequences.