*hardware accelerated OpenAL
*hardware wavetable with sound fonts sf2
*hardware mixing up 32 sounds in alsa so you can run several audio apps at once
*hardware dsp effects - you can upload dolby prologic compatibile decoder and use your card as dolby prologic decoder. And other effects.
These cards are the best for Linux when you look for hardware acceleration and features. They have weak codec, some little noise and are PCI only cards. So no PCI-E.