There is most certainly FUD regarding Mac being a better design platform. My impression is that you've got feature parity for most of the major design products coming out of Adobe/Macromedia... and a little voice in the back of my head is saying that new features show up for PC before Mac... but I'm not a designer and that's not the point.

Designers are a finicky crowd... they've got high aesthetics and Apple hardware and software appeal to that crowd. Design is a feel process... not a think process... and having tools/hardware which appeals to the feel side of your brain has got to be a win. INSERT HAND WAVING HERE.