I had a couple of Digimaxes for awhile, for the same purpose. I sold them, though, because ultimately they sounded OK, but not great.
I found a HUGE improvement by going to a True Systems TP8 and RME ADI DS converter or Apogee converter. Recordings came out much more airy, spacious, relaxed, and natural-sounding, with much, much improved low end. My tracks needed quite a bit less processing, fought each other less and sat well together. A tremendous improvement--bigger than my previous jump from a Roland VS workstation to the Digimax.