As an ex-C# programmer, I actually like String.Empty, and as a current Go programmer I wish there was an equivalent in Go. You present excellent arguments though in favor of "" over string.Empty though. I'm curious what if any performance difference there might be. Truth be told I think I always used string.IsNullOrEmpty() anyway, which theoretically should be slower than string.Empty().

Regardless, I absolutely agree that it should be a constant.