Headshrinker2, I'll add you to the growing list of audio consumers for whom the demo is dead. Bought another piece yesterday without a demo, but would have liked one.
Not knowing about Mac out connections, but if you are saying you connect your Mac to the optical input of the BDA, then you would find that balanced or SPDIF connections are usually preferable. And the USB connection from a computer is the least preferable.
I bought my BDP-1 without a demo and didn't regret it in the least. Indeed, this was one of the best things I've ever bought. But I went through the same kind of thing you seem to be doing - thinking how I could use my computer files, obviating the need to convert and move to a hard drive to be attached to the BDP-1. Then I stopped and remembered that the whole point of the BDP-1 was NOT to use a PC or a Mac, but rather a piece of equipment that does not need to suffer the degradations in sound that inevitably come from running signals from computers to high end audio equipment.
If you're looking for advice, for what it's worth, here is mine:
If you have confidence in Bryston equipment, which many people do (including me), and you have the money, buy the BDP-1 even without the demo, buy a large hard drive, convert your files to AIFF and copy them to the drive. Then hook up the BDP-1 to an ethernet connection. And if you have any extra cash, buy an iPod Touch or iPad - install mPod or mPad, crank everything up and be prepared for a thrill.
You might even find that unless you are doing business work on your Mac, you just might end up seeing it gather dust, as my notebook is no doing.
Dave