I recently read Cliff Stoll's excellent book 'The Cuckoo's Egg' about tracking early net crackers in the late 80s. It got me thinking about BSD Unix (Stoll was at Berkley using a very early BSD Unix). From what I can gather it was BSD's law suit with AT&T that allowed Torvald's kernel to take the high ground which resulted in Linux being the most popular Unix based OS today.
However, for me, the core of Linux is seriously disparate - endless kernel revisions, each distro with its own patches, file layout, start up scripts, endless dependency issues and so on. So I was very pleased to find this is not the case with the various BSD flavours. In fact I have just installed NetBSD on an old PC. It has a single source code tree that compiles on 57 different platforms which says a lot about the quality of the code. Its pkgsrc app is what gentoo is modeled on apparently and there are over 5000 apps to choose from (nearly as many as Debian).I am seriously tempted to roll it out across my other PCs.
Ian