MirOS BSD is a secure, desktop-oriented operating system from the BSD family for 32-bit i386 and sparc systems. It is based on 4.4BSD-Lite (mostly OpenBSD, some NetBSD®). MirOS BSD is one of the new BSD-based distros intent on improving the user experience of a BSD operating system, and making it more appealing for new users.
OpenBSD is a multi-platform 4.4BSD-based UNIX-like operating system with a near-perfect security track record – only 2 security holes since it was first released more than 10 years ago. Aside from the operating system, the OpenBSD teams is also responsible for OpenSSH, OpenBGPD, OpenNTPD, and OpenCVS
NetBSD is a free, secure, and highly portable Unix-like Open Source operating system available for many platforms, from large-scale server systems to powerful desktop systems to handheld and embedded devices. Its clean design and advanced features make it excellent in both production and research environments, and the source code is freely available under a business-friendly license.
FreeBSD is an advanced operating system for x86 compatible (including Pentium® and Athlon™), amd64 compatible (including Opteron™, Athlon™64, and EM64T), ARM, IA-64, PC-98 and UltraSPARC® architectures. It is derived from BSD, the version of UNIX® developed at the University of California, Berkeley.