FreeBSD is an excellent production server, and I use it all the time. And for "non-hardened" and "protected" production servers, the performance numbers went so

FreeBSD is an excellent production server, and I use it all the time. And for "non-hardened" and "protected" production servers, the performance numbers went solidly to FreeBSD for my use cases. Modifying the kernel from GENERIC to something specific to one's needs also helps. That said, I'm also OpenBSD fan, using it as a "hardened" (Internet facing) production server, with minimal ports, for things like Postfix, DNS, etc. OpenBSD is also well used in network management/control as a router, firewall, etc. Each has its use case, and does quite well in them.