I've only recently had to start using BSD, and FreeBSD is definitely easier to get started with.

Anecdote: I found a null pointer dereference in the OpenBSD httpd last week that allows an attacker to crash the server with a single crafted request. It's now patched.

I tried for a while to get a backtrace of the bug on OpenBSD, but their ancient gdb port doesn't support follow-fork-mode, and their clang port generates DWARF that their gdb port doesn't understand. Every time I reproduced the crash, the backtrace was just useless ASLR addresses. FreeBSD had none of these problems, and I was able to collect the backtrace in minutes.