I Feel Slower Now
During the first week of 2019, nomad ran OpenBSD 6.4. Here is how that went:
The good: Unlike under FreeBSD 10.3 a few years earlier, hardware support was better.  The Wi-Fi signal strength thing turned out to be i3status not supporting %quality under the BSDs.  5 GHz worked fine.  Suspension and hibernation worked well.  OpenBSD also does not have the headphone jack switching issue that FreeBSD has.
The bad: Performance was unacceptably slow.  If audio and/or video was playing, loading a Web page, even a simple one, in Chromium would cause the audio to stutter.  Swapping would occur when memory usage reached roughly 1.5 GB (nomad has 3 GB) despite adding my user account to staff and adjusting staff’s resource limits in /etc/login.conf.  It would avoid the rest of the RAM as if it were poison or something.  Wi-Fi was about half the speed it was under GNU/Linux for some reason.  Also, some Web sites, such as Twitch streams (mpv + youtube-dl worked fine, though) and Internet Archive’s JavaScript implementation of MAME, would not work in either Chromium (with sandboxing) or Firefox.
I have reverted to Debian GNU/Linux in the meantime. OpenBSD mostly worked, and I would have stayed with it, if not for the above issue.