For what it's worth to you: I couldn't notice a difference between my 0404's analog out and the CIAUDIO VDA-2 (w/ power supply) which runs about $800 together I think... so YMMV. That's actually when I became very skeptical of high end audio products. The 0404 is a professional card that strives to output a low-noise (NON audible), flat response and does so wonderfully (it's been analyzed and documented, a google search might turn it up) But this is also what any expensive DAC is supposed to do. I believe any "drastic" change in sound signature means you're either crazy or your equipment is faulty.
So I took the 0404 for what it was and use its EQ settings in patchmix to make everything I have connected to it sound like gold. But that also requires patience and a good ear.
I'm not saying you've hit the end of the road, but I do believe you've reached one of, if not THE top points of price vs. performance. Good luck finding what you need!