To give but one example, I recently reported a bug when FreeBSD didn't boot after upgrade from 13 to 14. Worse the disk format was somehow altered so when the reboot tried to boot off 13 due to zfs bootonce flag (supposedly a failsafe), it refused to boot for the same reason. I believe it's due to a race condition in geom/cam. The same symptoms were reported 6 years ago, but the bug report has seen no activity. Making your system irrecoverable without a rescue image and console access strikes me as pretty serious. He waxes lyrical about zfs, but it's slower and more resource hungry than it's simpler competition and it's not difficult to find numerous serious zfs bug reports over the years. (But not slower than FreeBSD's UFS, oddly. It's impressively slow.) Another thing that sticks in my mind is a core zfs contributor saying it's encryption support should never have been merged.
This sounds too disparaging because the simplicity and size of FreeBSD has its own charms, but the "it's all sunshine and roses" picture he paints doesn't ring true to me. While it's probably fair to say stable versions of FreeBSD are better than the Linux kernels from kernel.org, and possibly Fedora and Ubuntu, they definitely trail behind the standard Debian stable releases.
Comparing FreeBSD to Debian makes throws up some interesting tradeoffs. On the one hand, FreeBSD's init system is a delight compared to systemd. Sure, systemd can do far, far more. But that added complexity makes for a steep learning curve and a lot of weird and difficult to debug problems, and as FreeBSD's drop dead simple /etc/rc.conf system proves most of the time the complexity isn't needed to get the job done. FreeBSD's jails just make more intuitive sense to me than Linux's equivalent which is built on control groups. FreeBSD's source is a joy to read compared to most I've seen elsewhere. I don't know who's responsible for that - but they deserve a medal.
On the downside - what were they thinking when they came up with the naming scheme under /dev for block devices? (Who thought withering device names was a good idea, so that /dev no longer reflects the state of attached hardware?) And a piece of free advice - just copy how Linux has does it's booting. Loading a kernel + initramfs is both simpler and far more flexible then the FreeBSD loader scheme. Hell, it's so flexible you can replace a BIOS with it.
The combination of the best parts Linux and the BSD's would make for an wonderful world. But having a healthy selection of choices is probably more important, and yes - I agree with him that if you are building an appliance that has an OS embedded in it, the simplicity of FreeBSD does give it an edge.