I use both, since they do different stuff. I actually remote into my servers with wireguard, but I like to install tailscale as well as a backup. Since each device gets a unique tailnet ip, I can usually still connect even if I've fucked up some network config that breaks wireguard. ((If this is a security risk, someone let me know because I have no clue what I'm doing tbh.))

Plus tailscale lets you easily see what devices are connected to the internet at a given time.