On my x61s, OBSD as improved in performance compared to 5.7. With 6.1 promises it is time to reconsider the debian wheezy <-> OBSD switch.
OK! Let's go noob-technical!
My opinion as a not so experienced (but biased) OpenBSD desktop user:
-Performance: FBSD felt more responsive than OBSD around 10.1 vs 5.7. Now 6.0 feels fine on my x61s (with softdep in fstab).
-Hardware compliant: On my thinkpad, OBSD is just fine. FBSD couldn't suspend/resume, backlight did'nt work etc... Maybe 11.x will improve?
OBSD is NOT a features-OS, it won't follow every last chips. 3-4+ years-old non-nvidia thinkpads are your best bet but there are people currently hacking on chromebooks, HPs, etc...
For nvidia, go FBSD.
-ease of setup/use: OBSD wins here. For example: I couldn't shutdown/restart/suspend/hibernate with xfce. No worry, I opened the pkg_readme and spent 15sec finding the answer. Problem solved.
FBSD handbook is cool but I couldn't find my way as easily as I do in OBSD. A Linux desktop feel even messier compare to the BSDs.
OpenBSD has an oustanding audio stack/server (an audio server!! who would have guessed?).
httpd was easily set up too. Compared to Android where I will never figure out how to re-enable UMS or had to hack my through making my app able to write on sdcard.
-security: Can't speak much here, I have never been hacked (I guess) or run sensible system. First, are you planning to use only
base or
base+ports+3rd party+etc...
Security-wise OBSD's base seems a very safe bet considering the care given to the designs and implementations. I never mustered the courage to configure sudo but I feel confident with doas hence less miss-configurations. The code is maintained (read the reports of hackathlon on undeadly.org), the devs pay attention to details.
As soon as you build up your system with ports, you are doing compromises. Do you trust firefox? Are you sure the last vulnerability is patched in the port? Basically your system is as weak as your weakest port I suppose. So FBSD ports vs OBSD ports? Or maybe sandboxing (FBSD jails, linux sandboxing) vs OBSD pledge()&co (the most popular ports are being pledged) ? Is sandboxing a testing/developpement tool or a security mechanism?
With 3rd party software, the security question is less obvious. Your call...
For me it's OBSD+xfce+firefox+vlc and the likes.
-community: Both seems fine. I like Tedu' blog (doas basics in a blog post), bsdnow or undeadly.org for news. About the leadership, here, I believe a benevolant dictatorship makes more sense than a democracy. OBSD focus seems more defined than FBSD.
tl;dr
Write down your needs. Try both. Get an opinion.
P.S:
PF is more advanced in OBSD obviously and its SMP perfs is catching up FBSD.
About pledge, I suggest you listen to Theo making a comparison of security mitigation
https://www.youtube.com/watch?v=a_EYdzGyNWs Very instructing.