Preface: I have about 2.5 decades of Unix experience, and I have used Linux since 0.99.14. I have contributed a little kernel code to Linux, and at work I regularly do some kernel hacking (Linux and other OSes).
Having said that ... I use FreeBSD for one machine, which is my server at home. It is the NFS / AFS / CIFS / DAAP / HTTP server for the home internal network, and handles all the storage (including local backup and offsite disaster recovery) for the house. For the internal network, it acts as the DNS / DHCP / NTP / LPD / what have you server. It is the network router for the home network (connecting two wired one one wireless internal network, and the outside world), and it acts as the NAT box and firewall to the outside world. It is the access point for wireless at home.
And that last function is exactly why I run FreeBSD. For many years, I had been using OpenBSD, and I was absolutely delighted with it. Not because of the often touted security aspect of it, but because the file system layout, release and upgrade mechanism, and general system layout are so well done. Everything is minimalist, clean, and organized. You can set up an OpenBSD system that has very few moving parts; the amount of of unnecessary software is very small. But there is exactly one thing that in the end prevented me from using OpenBSD any longer: It's 802.11 AP mode stack is missing one vitally important function, namely it can't handle wireless clients that go into power saving mode. On some client OSes (Linux and Windows) you can turn "power saving mode" off, and they will work perfectly well with an AP implemented on OpenBSD. But there is one all-important class of wireless client devices where power saving can't be turned off, namely Apple devices (both MacOS computers, and iOS phones/pads). Since I can not legislate these devices away (we have too many useful Apple items at home, my kid and my wife would kill me if I told them to get rid of them), I have been forced to use FreeBSD instead.
Having said that: I'm about 80% happy with FreeBSD. Linux would be so much worse (today's Linux distributions have become so disorganized and fat, they make Windows look lean and neat), Windows is clearly not eligible for an internet-facing server, and I don't think I could teach a Mac to perform all these functions.