PC Engines uses coreboot for their APU boards (usually used as routers or firewalls).
The price/performance & energy efficiency isn't too compelling in my opinion, but if you like the idea of running your router, firewall or other network appliance on x86 with an open source BIOS and OS, its worth looking into.
EDIT: A list from coreboot site [1] does not look comprehensive as it is not mentioning Chromebooks or Purism.
[1] https://www.coreboot.org/Products