Hi,
It would be interesting to hear from someone who has actually tried both the EMU-404 and Audiophile 192. I think the EMU-404 also does 192 (I know the EMU-1212 does). So, both cards do support the same sample rate.
The big difference is in the DACs and perhaps associated components like opamps. I don't know anything about the M-Audio 192, but I respect the company. I do know that many people who have tried the E-MU (like me), have liked it.
Years ago, I did try the Audiophile 96 and personally compared it to Card Deluxe, RME, Echo Mia, and few others. As I recall, for the money it was a great card, but was bested by both the RME and Card Deluxe.
Since the E-MU has been compared favorably to the both the RME, Card Deluxe, and Lynx, unless the Audiophile 192 is a huge leap forward, from my experience with the Audiophile 96, I would give the nod to the E-Mu. However, there is a lot of supposition in this conclusion.
However, the differences in top end cards is not huge anyway, and you would probably not go wrong with either.
What I would like to find is a good card at a reasonable price that can output SPDIF 24/192. So far, the only two I have found is the new RME Hammerfall for $600, and the Waveterminal 192. The RME is a bit pricy and the Waveterminal has not received resounding reviews.