Honestly, It has been several months since I have used either. I think that linux could be consitered more mature, as far more people use is and work on improving it. But If you want something closer to the original roots; like System IV, bsd is what would be closest. If anyone feels that they may have an intrest in linux, but is not dedicated enough to install it on their system (or if the system is not their own to begin with). There is a live cd out, that runs the entire os on cd-rom, and a ramdisk: it is called knoppix, try it, you have nothing to lose: http://knoppix.com/. It has come a long way from version 3.2, and even supports ntfs.