Quote from Comptalk:
Spyware, viruses and malware are not currently present in either OS. Mac OS X is built off of a Unix kernal; such like Linux. Plus, with the little market share with both OS, virus writers target the 94% of world uses who use Windows vs the 5% who use Mac and 1% who use Linux.
Whether this holds in the future, I cannot tell you, but right now this is how it is. Ten years from now, probably the same just because of the huge market share Windows has on the world.
Macs are usually the easiest to use. Linux is not as difficult as it was several years ago. However, the problem is the lack of support major programs have for Mac and Linux. Tradestation or Esginal do not support Linux or Mac. Thus I have to use the service in VMWare Fusion to emulate Windows so i can trade.