Ubuntu/Raspbian… I was not aware that this exists. Do you mean some Ubuntu distro for ARM?
NC from packages, there are none for ARM AFAIK
Docker image: easy to install on any system that runs docker, so it would work on Ubuntu, if you want to use Ubuntu for any particular reason (I prefer Debian).
NCP image: nothing to install, works out of the box, and more featureful than the docker image. This would be my recommendation.
I really like the Odroid HC1, I am working on it ATM and it’s so much faster. I would need to find some time for further optimizing for it, but it is already much better than RPi.
If there’s powerloss… systemd will check the system upon next boot most likely. If you use BTRFS (NCP default), it has some better self-healing capabilities. But always, keep backups/snapshots.