I have an A20-Olinuxino-Micro with a battery, so the device can cleanly shutdown when power is lost.
I strongly recommend only buying devices that are compatible with Debian main, or mainline Linux at least. Usually I just check if it's compatible with Debian main, and if it's not, I move on. The latest shiney SoC is not worth the software pain caused by uncooperative manufacturers.
Recently had a power cut that killed the system, but rather than reinstall I poked around for a few hours until I discovered the bootloader's zImage had been corrupted. Copied another over from the original install image, and away it went.
When I find myself a decent job, I'll dedicate a more powerful system to the task, maybe virtualize a few of the servers.
Fun projects, although there are many head-hit-keyboard moments in setting it up.