I assume the comment you are responding to was about the init-system and in extension to the much more straight forward design and implementation of the overall

I assume the comment you are responding to was about the init-system and in extension to the much more straight forward design and implementation of the overall system. FreeBSD is, like all(?) other Unices written in C, as is most of the userland. > userspace must match kernel Just as far as it is true for Linux. If the interfaces don't change, the userspace tools will happily talk with any kernel. In now 19 years of FreeBSD usage on all my servers and on my laptop I ran into problems caused by a mismatch kernel<->userspace maybe 3 times. OTOH, the comparison is unfair with BSD-boxes reaching uptimes > 1 year easily.