i've been following the nightlies for droidTheory's AXI0M AOKP builds. thankfully i have had very few data issues, using it as my main currently (lol even though i just picked up a bionic lapdock and should really go back to GB, i can't get enough of ICS!)
its hard to say with any certainty that it sounds better than DSP Manager or Beats (meh) audio patch. truthfully, it's all going to be highly dependent upon your set up.. i dont use headphones AT ALL, only place my bionic serves up tunes is in the car, and it's only lossless FLAC at that. i do have to say, however, compared to out of the box performance from a few months ago, the ICS ROM sounds much clearer. i'm currently using the headphone jack audio output, however, i think i'm going to order this "special" motorola Y-cable that comes with the car dock (got mine through verizon and NEVER EVEN KNEW about this grr), might be able to clear up the remaining hiss. i have the HD dock as well and while some people report no background hiss from the 3.5mm jack, i still hear it unfortunately (my well-duh! moment: our phones DO output audio through USB, just not usable without someone investing some time into USB host functionality..)