Well, that depends on what you want for your game. Do you need psionics? How about genetic enhancemnts? There are some great general prestige classes too, like the Sniper. What kinds of things are you looking for specifically? I personally don't run SFA, but I use the book all the time.
While there is a lot of setting-specific stuff in the book, there's also a lot of crunch to it. Psionics, extra gadgets, new feats, and plenty of plot hooks. Yes, yes, I know that the plot hooks are setting specific, but there's nothing to say that you can't yoink the bits you want for your own setting.