Needs/requirements:
Low power at idle (lets say 20w or less, lower is better) as the highest priority
Not a vendor locked platform, so either x86 or something that could run a hypervisor.
2+ Gigabit ports (not realtek, or troublesome) and/or at least one PCIe slot
Either ATX power or NON proprietary DC power (nothing that must have a specific OEM power brick).
Cost, Under 200. Cheaper is better. I prioritize this over max performance.
The intended use is as a backup firewall for extended power outages so it will be running on solar/generator/battery. Thus passing traffic at 1G is nice to have but if not thats fine. I already have cases, power supplies, ram, NICs etc so a bare board or barebones option is fine.
I've looked at the tiny mini micro thread and it seems like the ones with 2+ ports or pcie lanes are both higher performance and higher cost than I need.
Yes, I am looking at more batteries etc, but all of that adds up too