Unicode and Macs

Following on from my Unicode Lament, Ken Ristau comments (but please use the "Comments" facility and not this, "Old Comments" facility, which is there to keep the older Haloscan comments alive and will be dropped in due course) and Jim Davila emails to point out the problem re. unicode and the Mac. I am afraid that I am ignorant about Macs, but what I do know is that whenever I mention them here I get an avalanche of comments and emails, so I wonder if anyone is able to answer the question about unicode and Macs. If there is a significant problem with using unicode on Macs, I will agree that we should not all be quite so hasty in changing to unicode, and we'll have to stick around with SPIonic for a bit longer, but I'll bet that there is a good answer. Anyone?