depends on the budget,
depends on your ear/brain, if it likes more color sound or grey sound.
too many variables.
like jitter.
wordclock, the op-amps in the DAC., the circuit design in the DAC.
wordclock & s/pdif cable velosity propagation, and capacitance.
toslink vs. s/pdif,?
depends on the s/pdif cable used.
if its a good cable will have way lower jitter than toslink/adat/madi.
but if its a bad cable, will have lost data.
s/pdif with a verry nice cable will sound more detailed., less muddy, more transparent,
but that also depends on the wordclock you have also.
0.03ppb, <1ppm, 5ppm, 25ppm, 50ppm like alesis ai-2
, digital DDS or PLL, TTL, Crystal, TCXO, OCXO, etc..
some wordclocks allow to reclock, and resample. like drawmer m-clock, antelope DA, etc..
some DACs have jitter elimination mechanisms,
but none are better than a rubidium atomic clock.
if you plan to upgrade to an atomic clock, try to avoid DACs with a jitter removal mechanism that cant be turned off. "Wide lock"
some DACs have fixed SRC, and SRC creates distortions.
http://src.infinitewave.ca/
make shure you like the distortions.
3daudioinc c0m has a nice ADCD double cd comparing ADCs, but usually ADC has same sound as DACs, if done properly
becouse has the same analog circuit design, and same wordclock.
reb box rb-adda 96k sounds really nice to me,
lavry gold the best ive heard.
i dont like prism AD/-DA-2
i like black lion modifications on the digi002r
etc...etc...