Comment by rainsford

Having tried both Zerotier and Tailscale, I found Tailscale to be a significant improvement. Tailscale uses Wireguard as the base encrypted protocol instead of a semi-homebrew protocol Zerotier came up with that notably lacks things like ephemeral keys/perfect forward secrecy. Tailscale also has a faster pace of improvement and is responsive to customer asks, regularly rolling out new features, improving performance, or fixing bugs. Zerotier by contrast seems to move slower, regularly promising improvements for years that never materialize (e.g. fixing the lack of PFS).

My last gripe is more niche, but I found Zerotier's single threaded performance to be abysmal, making it basically unusable for small single core VMs. My searching at the time suggested this was a known bug, but not one that was fixed before I switched to Tailscale. Not impossible to work around, but also the kind of issue that didn't endear the product to me or inspire confidence.