Considering how easy it is to port software from Mac to PC, and vice-versa, my guess would be that they will be released at the same time. This would be a deal with the producers, as they know that it's PC users who will fill their accounts. Also, as far as I know, other than hot-key commands the Mac and PC versions of Bryce have all been identical, which makes for fluid transitions between work and home. Even the Bryce project (.br?) files themselves are portable between platforms.