I'm using the akashic in my Dragonlance campaign, but there isn't much else from the book that sees use. My wife, who's playing the akashic, has also complained a little that while it seems like a good class at first blush some of the abilities in the first 3 levels seem fairly unimpressive. It's turned her off further advancement, since other characters who have bardic knowledge-type abilities seem just as capable as she and yet hers is supposed to be tapping into the collective knowledge etc etc.
I've been using racial levels, although it's not something unique to AU, and action points, which are a very common feature in gaming these days. Mine work more like Buffy: the Vampire Slayer's drama points than AU's hero points, as well, so in reality the various house rules or included OGL/d20 rules in my game aren't so much AU rules as they resemble them through parallel development.
Cheers,
Cam