The issue with crunch is that it's going to turn to dust in a few months for anyone who wants to convert their campaign to 4E; as a result, the emphasis was more on flavor that would remain constant. In terms of player options, there are a few things - a handful of feats, a few class options, a few spells - but the bulk of the crunch comes in the form of nine organizations players can join, along with affiliation benefits. While these benefits will still need an transition to fit 4E, the bulk of the entry will remain valid for both... while something like a prestige class might not work at all.
So, it's a tricky road to walk, being the last book before 4E. I think there's good material that will be useful both to people who keep their campaigns in 3.5 and those who jump them to 4E, but if you have the opportunity it's always worth looking at the book and judging for yourself.
