In this article by the Brio Team, Linux and FreeBSD are compared in terms of its developers, security, licensing, and compatibility with hardware and software. The author also explains which one may be a better fit for a specific user. In addition, it discusses the UNIX element of each kernel.
For most users, the difference between Linux and FreeBSD is not something significant, as the two operating systems frequently share even the same applications. Both of these Operating Systems are UNIX like, in their form and function; while they are developed mainly for non-commercial interests. However, on taking a closer look one can uncover more differences between the two.
Check out the full article here: http://brioteam.com/linux-versus-freebsd-comprehensive-comparison