louis, (edited ) 
First full evening using exclusively #OpenBSD installed on a ThinkPad X1 Carbon Gen. 8.
Base install was ridiculously easy, installed XFCE4 for a little more comfort.
After replacing apmd with obsdfreqd from @solene - power management is excellent, fans off most of the time and battery lasted all evening.
OpenBSD does not support Bluetooth at all, lucky I still have an old Logitech mouse with a USB dongle.
Firefox is usable but without DRM support and a bit sluggish. Ungoogled-chrome works well. SMT support can be turned on with a single config line.
Emacs, of course, works well with the exception that I couldn't get UTF8 characters to display, I need to spend more time on that.
If you need proprietary software or projects with such components, OpenBSD is not it. Which makes it so fun.