BSD system has nice build and apt manager. In fact, that's where Linux variants like Gentoo get their inspiration from. There is nothing more satisfying than building everything from scratch, seeing lines and lines flying through the screen (that is until there is a build error.. and you start to get frustrated). But other than that, I agree it is a good system to learn from. I did not start off FreeBSD though as I actually started with OpenBSD (comparable to Debian of Linux)