WireGuard is the protocol all three products are built on, so "WireGuard vs Tailscale" is the wrong framing. The real question is who runs your control plane: Tailscale's SaaS, a self-hosted Headscale, NetBird's fully open stack, or nobody (raw WireGuard). This guide draws the protocol-vs-control-plane-vs-relay map cleanly, compares the four on the dimensions you actually decide on, explains why kernel and userspace WireGuard perform differently, and gives an infrastructure operator's verdict, including the angle the vendor-written SERP ignores: mesh access into management and out-of-band networks.