I used FreeBSD for a good few years, and picked it up around the same time I learned to use Linux. In that time, I found it to be a great operating system, with a lot of good ideas, and simple implementations for the user. It ended up doing some good work for me, until I realized I needed to do more with my computers.
I've used FreeBSD as a workstation operating system, and it really doesn't bring anything to the table in that regard over Linux. Speaking practically, GPU drivers tend to be a lot more labored, there will be things you didn't even realize were Linux only until you need them, and even when you do get everything put together, it'll just end up feeling the exact same as a Linux workstation system. The only advantage I could see, is the FreeBSD model of stable base system combined with rolling ports is /excellent/ for a workstation user, as it gives you recent software, while almost never putting you into an unbootable system due to updating your packages.
Therefore, FreeBSD was largely a server operating system for me. I can proudly say that I managed to run, as one of my first real internet projects, a 80-100 million connection/mo BEMP (that's BSD, Nginx, MariaDB, and PHP) cluster, using nothing but FreeBSD. ZFS out of the box was excellent, and stable base + modern ports wasn't a bad mix here either.
However, sitting here, having not too long ago moved to Debian for all my servers, I can say I would have absolutely not done it the same way. ZFS on Linux is stable, and despite being a minor pain to get going, works just as well as FreeBSD. A lot of the software is far more optimized on Linux, with my now LEMP stacks having far faster response times, and far less CPU load for the same workloads. I found across the board, especially in compute intensive Java workloads, that Linux just ran faster. The Debian project is a marvel of open source software, and despite FreeBSD being famous for shipping an operating system not a kernel, I still find Debian to be the more polished option.
And then there is this:
https://vez.mrsk.me/freebsd-defaults.html which for me was the final nail in the coffin. A lot of the time, even if we think we know what we're doing, we're ultimately reliant on the people who write the software we use to know what they're doing, and make responsible choices. While I'm sure for a lot of what's said on this page has more than one side, from the digging I've done, I'm honestly disappointed with what seems to be a project more interested in chilling in the 90's than in writing a safe, secure operating system.
I'm no expert, this is just my personal experience, and I'm sure half of what I've said is wrong. Just take it from my experience that just because it looks cool, and just so happens to be to Linux as Linux is/was to Windows, it doesn't mean that it's actually worth using. For servers, I use Debian, and for my workstations (primarily for convenience in installing weird software, the AUR is awesome), I use archlinux.