The learning curve seems vertical at times but I'm finding FreeBSD quite refreshing. Ports and pkg-ng are great (although Australia really, really needs a local mirror).
The files I need to boot from live on a USB thumbdrive and I've got IPMI to the box so I'm not too worried. I think buildworld would be pretty slow on this box (Atom C2758). I'll give it a shot.
I don't really need vnet but having IPs per jail and some kind of network seperation made more sense to my brain.
I made a tiny tool that spins up a jail with nullfs/unionfs mounts and RCTL resource limits from a single JSON/UCL file: https://github.com/myfreeweb/sandblast
It also has nice ZFS support. Here's a short, well written, howto showing an ezjails+PF+ZFS install/config process: https://forums.freebsd.org/threads/30063/
0 - https://www.freebsd.org/cgi/ports.cgi?query=ezjail-3&stype=n...
Slightly risky way: you can run freebsd-update fetch and then install twice, and you will notice it updates /usr/src.. it will instruct you to reboot after the first install, but instead do another install and you will notice that /usr/src has been updated. Rebuild your custom kernel and reboot. You risk changed ABIs during this, in practice it may be fine but depends how much you care about the box and whether you are comfortable cleaning up from a chroot if things go really bad.
Better: use svnlite in base or real SVN to update /usr/src to the releng/10.3 branch. Build your kernel, reboot, do freebsd update to get the base updates and make sure your kernel is intact.
Best: use svnlite to update /usr/src. Do buildkernel, reboot. Do buildworld and follow https://www.freebsd.org/doc/handbook/makeworld.html. The more you run FreeBSD, the more you will want to follow -STABLE or -CURRENT and do your own release engineering.
Future best: Use any method to derive custom kernel, use packaged base to update base. Or again hopefully common use wont need a custom kernel.