Joe,
First off, make sure you're posting in the right forum. :)
Short answer: if you're asking about Windows OS vs. Mac OS, there's not a lot of difference as far as SSL is concerned, you should choose the one you're most familiar with.
If you're asking about Apple hardware, it's really a comparison against other premium laptops (Sony, HP, IBM). Comparing a MacBook Pro to a $899 Dell really isn't doing you much good.
Finally, there's only one machine out there that can run both OS X and Windows, so if you're on the fence or need to run both, (and have the budget) get a Mac.
See my entries in this thread:
scratchlive.net