I use an SBLive! Value, it works fine in 98SE/2000/Linux
A3D is better positional than EAX, but EAX isn't even suppose to be for positional audio. It's for environmental effects, I think these are cool, some people think they suck, but either way EAX isn't positional, SBLives just use DirectSound3D for positioning.
With Aureal dead and poor vortex2 Win2k drivers, and no future enhancements to A3D likely, the Vortex2 is a bad choice for a sound card. I hate to say it because they are sweet, and A3D is pretty nice...but with no future support it's kind of useless
Just a sidenote creative owns A3D now, so if there is any future support it will come from creative in their sound cards (probably something new, not the live) but certainly not for the Vortex2.