Yup, the sibling comments mention a few alternatives (FreedomBox and Yunohost) but Sandstorm is really the only one I've ever used that makes me confident in the state of the system long-term. Let me elaborate on that.
FreedomBox and Yunohost use more traditional software installation mechanisms; they'll install packages, run scripts, etc. They just add (sometimes very nice) UI around it. While that's great for some things, after a while things can get a bit messy. For example: what about when a package installation fails for some reason? Or one of the configuration scripts fails? Well, you're stuck logging in and troubleshooting, which isn't super fun (and might be intractable for less technical users).
Sandstorm, though? Everything is sandboxed and isolated from the rest of the system. Everything. Backing up or restoring an instance of an app is a few clicks in a web interface. Sandstorm handles auth so the app doesn't have to... etc etc.
This has its downsides, namely that apps that aren't written with this sort of usage in mind might not fit in as well. But for those that are, it's by far the best experience I've had. I have Yunohost and FreedomBox servers in varying states of disrepair, but my Sandstorm server keeps chugging along. Big fan.