...Its infact devloped by some of the old sonique users and was originally written(and now taken back up after switching back from mac recently) by one of the main original sonique developers (tony million)

anyways tuniac always handles formats as 32bit floats(anything less is padded) and then kmixer will convert to the best suitable format for the installed soundcard. this simplifies things greatly inside coreaudio(the balls of tuniac)
It can also handle via a well thought out plugin system nice highend sound like 24bit ape and mp4/m4a and multichannel sources (eg 5.1 ogg wink ofcourse creative drivers have a bug that prevents 5.1 on waveout completely and also when using 32bit floats(16/24/32bit ints are fine) in directsound so tuniac will give an option soon for doing 32bit float to 32bit int to bypass the driver bug))
And has oE5(custom opensource mp3 decoder which is a complete rewrite from sonique2's aE4.9) ofcourse differences in mp3 decoders are always argued about, just go with your heart if u feel their are positive differences between decoders

Anyways use what sounds nice to you.. most our uses have atleast audigy2zs's or above(seems the closer the person to the project, the higher end the gear gets) or simply use tuniac cause of how it feels. btw most arent using tuniac on pc speakers solely and have decent hifi components/speakers