Ok thanks HiFidFan! Schiit always promote Bifrost superior so surprised!
In my opinion, It all comes down to their proprietary reconstruction filter that they call SuperMegaComboBurrito. It sounds very slightly different to a typical sigma-delta filter, at least to me. This small difference is somewhat apparent in percussive instruments such as cymbals and hi-hats.
For all other purposes, it is impossible for me to pick out the Bifrost 2 in a level-matched blind test against a well-designed D/S DAC such as the EL DAC II.
I think that the part of the satisfaction in owning and using components like the Bifrost 2 and the Asgard 3 comes from the knowledge that they are customized designs that use proprietary technology and, almost exclusively, discrete parts. In theory, this could mean that the designer had more control of how the final products sounds/performs. Whether this is true or not is up for debate.