I have been using FreeBSD for almost two decades now (and still use it) both privately and professionally. I stared at 'dark' 5.x times with problematic SMP implementation and DragonflyBSD split.
These back then in 2004-2005 were the 'dark times' for FreeBSD.
Since then all things improved or been reworked.
Besides ZFS inclusion many great things happened in FreeBSD that are not available anywhere else like:
- GEOM Storage Framework
- Jails with VNET or Netgraph networking
- Bhyve virtualization/hypervisor written from scratch and ported to macOS and Illumos
- new LUA based loader(8) with support for ZFS Boot Environments - beadm(8)/bectl(8)
- TLS in kernel (Netflix)
- imported DTrace for better troubleshooting and looking for performance improvements
- Capsicum sandboxing Security framework
- 33000+ available packages in pkg(8) repository
- support for new/latest GPUs
- boot speed improved from 28 to 8 seconds: https://youtu.be/10XRCiBtyhA
- import of pf(8) OpenBSD firewall
- ported to ARM64 and POWER64 architectures
- move from M:N to 1:1 threading model in SMP
- new bsdinstall(8) installer and bsdconfig(8) companion
- sendmail(8) removed for dma(8) from DragonflyBSD
- ... and I definitely do not remember tons of other stuff (almost two decades)
Not to mention BSD license that gives you ABSOLUTE freedom and not just a glimpse of it.
Some of these features I described here:
- https://vermaden.wordpress.com/2020/09/07/quare-freebsd/
Regards.