The similarity is predominantly between the userland. (The Freebsd kernel and XNU is mostly historical as far as I know)

A typical Linux user will be used to GNU conventions and probably have a lot of annoyances.

GhostBSD is simply a beginner friendly distro of FreeBSD.

In one line both MacOS users and BSD broadly will squirm at the likes of things like `ls src/ -la`

But honestly, I was interdicting in the idea that Linux is the only alternative really.