Get what your saying Martin re: Wav format, and whilst its true both Wav and Aiff are "uncompressed" PCM formats (as opposed to lossless), I think they store data on the disc differently?
One has the most significant byte first and the other one last...does this make a difference anywhere except on paper though?
Don't know don't really want to think about it too much, (less FUD the better), but I listened to the same tracks in both formats and there was worthwhile improvement to my ears (and a couple of mates) using AIFF.
iWas so convinced of it I converted all my Flacs to Aiff.

Looking at it logically, I think it may come down again to the "less is more" way of thinking?
Perhaps the way AIFF files are stored on disk requires less processing, hard drive crunching or memory overhead before playback, albeit probably very slightly less.
Thinking along the same lines of why Wav is potentially better an Flac, despite the fact bit for bit a Flac file is exactly the same as a Wav...But only AFTER its been converted to PCM.
Not offering this as a reason, just as a theory, may be barking up the wrong tree totally.

Thing is though, for me it all comes down to what sounds better, even if its just a slight improvement it's worth having.
I've found everything, no matter how small, can make a difference.

One I'd like to try out is Broadcast Wav, apparently used by many recording studios as the "best" recording format, though e added features like timecode data etc might not translate to better audio quality.
Also there's the question of compatibility...but could be fun to give it a bash anyway.