I've tried Nebula before, admittedly a while ago, and it seemed interesting, but much less user friendly than Tailscale. But one of these days I would like to play around with defined.net just to see what other options are out there.

I also tried ZeroTier and was extremely unimpressed, although again that was a few years ago. The performance on single threaded systems was absolutely terrible, which suggests some deeply broken code and made it unusable with a cheap VPS. The paceof development was also pretty slow and the insistence on homebrew crypto was also not confidence inspiring compared to something that used a proven solution like Wireguard.