What advantages does it provide
ZFS, mostly. There are some smaller peripheral things (like much better manpages), but these days the big one is probably ZFS. Zero licensing conflicts allows it to be an integral part of the kernel.
like better manpages
I want them now! I want the better manpages! Has someone decided to create inproved manpages for Linux? I think this could be a great idea for a project or an organisation. Manprove, the organisation to improve Unix manual pages.
FreeBSD 13.0-RELEASE switched to the OpenZFS implementation[1]:
The ZFS implementation is now provided by OpenZFS. 9e5787d2284e (Sponsored by iXsystems)
So no big differences now, except for the licensing.
Linux is licensed under the GPL, which is described as “copyleft.” The GPL requires that if you want to use GPL code you need to license your modified code under the GPL.
FreeBSD is licensed under the BSD license, which is a permissive license. Basically as long as you stick the license statement in your documentation you can do whatever you want with BSD-licensed code. This is why commercial uses (like the Wii’s OS) tend to be BSD-based rather than Linux-based.
