I have mixed feelings about FreeBSD. Some stuff is genuinely good: major/minor release branches, the best ZFS experience you can get OOB, actual man pages, overall a lot "cleaner" than most Linux distros.
OTOH when you compare it to e.g. OpenBSD (or in many instances, even Linux), it's an actual mess. The default install leaves you browsing thru the handbook to get simple things to work; it has three (three!) distinct firewalls; the split between /usr/local/etc and /etc constantly leaves you guessing where to find a particular config file; even the tiny things such as some default sysctl value being an XML snippet - actually, WTF?
The desktop story is also pretty bad. OpenBSD asks you during installation, whether you'd like to use X11 - and that's it. You boot to XDM, you get a basic window manager, things like volume buttons just work, all in the base system - no packages, no config files. You can install Gnome or XFCE from there, and rest assured you'll always have a working fallback. FreeBSD still feels like 90's Linux in that area. Regarding usability, both are behind Linux in things like connecting to Wifi networks, but in OpenBSD's case you just save a list of SSIDs/passwords in a text file, and the kernel does the rest for you.
The author is praising jails. I think it's nice that you can trace the lineage all the way back to 6.x, it sings a song of stability. You can also put each jail on a separate ZFS dataset to get snapshot/restore, cloning, etc. But I think it's still a poor middle ground between OpenBSD and OCI. OpenBSD keeps making steps (privsep, pledge, unveil) to provide isolation, while remaining conceptually simple for the developer and imposing no extra maintenance burden on the operator. Containers by design are declarative, separate the system image from state, etc - it's a wholly different concept for someone used to e.g. managing stateful jails or VMs, but it reinforces what already were good design principles.