I have to largely agree with you Bunnyears. My main point is I don't particularly care about obtaining "best" versions - what I think is best can vary from day to day and be affected by any number of factors, like for example my wild mood swings. So faced with this I am happy enough to have a general indication from a review that an interpretation is not hopelessly misguided, and reaches a certain quality level, and after that its over to me to enjoy getting to know the interpretation, disagreeing with details, seeing new interpretive points, discussing it with other people, comparing it with other versions and coming to some kind of overall opinion. This includes appreciating the regional biases, and sometimes trying to hear the music through other people's ears.
This to me is much of the enjoyment of listening to music - its a living art that you can interact with and react to. Unluckily recording can turn music into a dead museum piece, in which people come to think that their "reference" recording is in some way the best, or even worse, the only way a piece should sound. Now thats the danger of these books, but use them as a general guide to quality and they are mostly adequate, as well as being a good guide to repertoire, whether an overview of a composer or alerting you to material you might otherwise have overlooked.
I might add (just in case anyone thinks I am being insultingly obvious!) that I realise that most of us here seem to enjoy music for these qualities - we wouldn't be endlessly debating the merits of various Bach cantata cycles if we didn't truly enjoy the differences!