I had enough problems that I had to stop using it, though when it worked it was fantastic.

Client intermittently had seizures (at least on Windows) and I couldn't join/unjoin networks properly. Would have to restart the service and close the program for it to begin to work again.

Sometimes the traffic just didn't flow ... at all. Randomly couldn't connect to other clients on the network.

I quit about 6 mo ago. Has it improved since?

I haven't had to use it much since covid started as I'm mostly at home these days and I used it to access my LAN when I was out.

I have tried to use it over mobile data and wasn't very lucky, and that's something that used to work great. I couldn't tell if it was due to ZT or the carrier. There's CGNAT on both ends, which could be getting in the way, although like I said it used to work great.

I have also noticed that it takes longer than I was used to get IP, find routes between nodes, etc but once those are up it works well.

I've used Zerotier for several years now, and it does feel that the stability on mobile has improved in the past couple of months.

I feel like my whole life got simpler with less headaches when I discovered ZT. I adore it. Maybe there are other things out there which do the same thing but ZT is the single 'it just works' thing that has made my life easier the most.

Not associated with them in any way other than being a user.

It has a bunch of other functionality including virtualizing at layer 2 and a distributed rules engine.

... and "public" VPNs, where all you need is the network ID to connect. Seems great for playing LAN games. It also has a userspace implementation, which I was able to use on bitbucket CI/CD where I couldn't bring up a tun/tap device, to connect via SSH to a private server. It also has Ad-Hoc networks that are public, IPv6 addressed, and based on port-range, so you can expose your SSH server to anyone with the IPv6 address, for example.