Hi Spaz,
In terms of the bitstream (data) being passed from the DVD player to the receiver, neither type is "better" qualitatively than the other (coaxial vs. optical). It's just on and off pulses in a binary code. However, if you have an optical output, there is no possibility of electrical interference or hum pickup because it's an optical signal. Using a coaxial cable there is a remote possibility of hum or interference although I've never experienced any. There is absolutely no difference in the "sound" of either type of digital connection.
Regards,
