I'd maintain BSD is more arcane but there are less ways to shoot yourself in the foot with OpenBSD than with Linux. The design is coherent and still minimalist sticking to the UNIX design philosophy. BSD doesn't have systemd which suffers horribly from scope-creep (HTTP server for journal events (WTF), binary logformat, default to google resolvers[1] ...). All daemons of the base system are chrooted by default. Base systems has also really good hardening which is unmatched on Linux. (Linux has AppArmor or poorly managed SElinux out of the box). Also auditing. BSD code gets audited by people with a security mindset who I happened to follow and respect since a very long time. As a C developer myself I am confident to say they do know how to think in these terms, while the Linux maintainers are known for hurling abuse against anyone who raises an issue (if you're that lucky to be addressed more likely topics that require design considerations and not just fixes will get you ignored). It's miles apart in that sense.
All in all you need to be much more skilled to harden Linux (which gives plenty of opportunity to trip up). I could go on and on.
These are all security relevant issues imo.
On a more personal not it appeals to me because the community is incredibly knowledgeable. Like it was with Linux 10-15 years ago and before main-stream users clogged up the forums with "how to change my desktop". I know this sounds elitist but being strapped for time it really is refreshing not having to wade through hundreds of copy/paste blogs that are all outdated and obviously written by hamsters.
You can go back and forth about the marginal security differences of the two platforms and how typical and optimized security configurations alter their total security.
But in reality, they're both very similar operating systems with fundamentally similar security models. It's a little like arguing about whether Python is a more secure programming language than Ruby.
