i've used both mac and pc
and with the amazing speed their at now. i don't think it matters anymore
what matters more is how the programs you like run on them, and that's a matter of perspective.
for me, mac is great for midi/timing
and the pc is perfect for audio manipulation
but i like the way a pc handles files better, i like to know where everything is and what it does, and with a pc it's easy for me to do.
but that's my $0.02