The Go version may in fact be faster, but I don't think that's necessarily fair either: if the Go version adds features to be more comparable to nginx it would definitely slow down.
Good point. That is often how alternative parallel implementations are started. A small example is written. Benchmarks are published. The new project is hailed as better than predecessor. Many jump ship. Request for features comes in. New features starts to slow down the product. Someone new comes, writes a simple benchmark and so on.
* Are they relevant. Does this represent the expected production workload. You could find this is 10x better than nginx at some feature but that feature is just not interesting to you then benchmarks are not that interesting
* Does the speed difference matter? Does it matter if the page loads 1ms faster when it was only 20ms before.
* Does it scale. This kind of relates to first question but it looks at abnormal amounts of traffic (Slashdot effects). Either from an attack or just becoming popular too quickly. If simply adds a server with more CPUs would that let Go server scale better than nginx? It might even though nginx could probably process sequential requests faster.