My Bifrost Multibit upgrade arrived yesterday and is installed, though I had problems with the new C-Media USB driver. It's been 'On' for >24 hours and played for abut 6 hours.

The upgrade includes a new analog section as well as the new DSP and DAC. My main impression at this point is that it delivers a significantly, (not to say giganticly), better resolution. This translates into not just more "detail", but more spatial information, firmer imaging, more define instrument decays, and sweetness in the mid-range and highs. I think the deep bass might be a bit improved too.