I have been running OpenBSD and PF on a PC Engines APU[1] for my gateway router/firewall at home for about 5 years now and the thing is rock solid. I just love the minimalism and simplicity which is likely the source of the incredible stability of the platform. Besides updates or modifying PF rules I have never had to touch the box.
[1] https://pcengines.ch/apu2.htm