My understanding of the Aureal story is that they were basically Media Vision reborn under a new name, and suddenly burst onto the PC scene to start a 3D audio revolution that would continue on up until 2007 (when XAudio2 + X3DAudio and FMOD Ex started becoming dominant for PC games with inferior audio mixing; I'm still pissed about that).
They actually pioneered binaural HRTF mixing, though most people wouldn't have known the jargon. All they knew is that they could suddenly distinguish front and rear, and even high and low, with nothing more than a pair of conventional stereo headphones (and probably stereo speakers too). Aureal could have very well been the first company to know that games should have treated headphone users to something better than one-dimensional left-right panning.
But then Creative decided they were too much of a threat, so they sued Aureal...and Aureal countersued. While the courts ruled in Aureal's favor, it was ultimately a Pyrrhic victory as the legal fees apparently bankrupted them, and then Creative bought them out shortly afterward, effectively overturning the legal rulings anyway and killing off their biggest competitor.
I'm not sure how true or false the story is, but it is pretty sad. I get the feeling that had Aureal survived, PC gaming audio would not have had a major regression over the last 5 years once everyone got fed up with Creative. (And since Creative has all the good 3D audio tech under their iron grasp after their Aureal and Sensaura acquisitions, you see where this is going...)
Also, consider me an envious bastard due to the fact that you have an SQ3500 Turbo. How much did it cost you to get your hands on that thing? For that matter, are there any drivers out there that will make use of the DSP daughterboard, or is it just collector's dead weight since Aureal didn't have enough time to code drivers for it?