The Art Dio is pretty cool for the price. You get two mono 1/4' unbalanced inputs to create a stereo signal. You get two mono 1/4' analog outputs to form a stereo signal only when there is a digital signal going into the input of the Dio. Has exceptionally good analog output and good clean digital ouput at 24 bits (can't select any different bit rate) as well. The tube warmth thing is cool but doesn't really drastically change the audio in my opinion. At 48khz sample rate, it sounded pretty similar to the soundblaster 64, but with much more dynamic range. I don't know what it sounds like at 96khz because my digital soundcard can't record at tha t sample rate.
The only thing I could complain about is the lack of balanced inputs but is no real biggie. If you're poor and your soundcard sounds noisy and nasty, get it. Remember, you need a digital coaxial input set at 24 bit though!