I used it for a while, but found it to be unreliable. Sometimes my Raspberry Pi’s became unavailable through the nebula network. I had to ssh into the Raspberry from home network and restart the nebula service. This happened once a week or so on Zero W, so I tried Tailscale. It was much easier to set up than Nebula and works better for me so far (3 months).
> Nebula is a mutually authenticated peer-to-peer software defined network based on the Noise Protocol Framework.
It's self-hosted and I think it's a great alternative to ZeroTier, or Tailscale.
I believe its been powering Slack's overlay network for ~5+ years.
[1]: https://github.com/slackhq/nebula