About V8 JavaScript: "Slow, because compared to C, Crystal or Go, it's slow."
In my experience writing real world server programs, Node.js is faster than Go in many cases. Part of this is a lack of Go library maturity, but it's also due to the fact that V8 optimizes code at runtime based on how it's being used. This project seems to come from a naive, "interpreted slow, compiled fast" view of the world, leading to false assumptions like Go is going to be automatically faster than Node.js because Go is AOT compiled and Node is JIT compiled.
I can't speak to Go or Crystal. V8 performs well on microbenchmarks, but very poorly with a sustained high volume of input due to GC pressure. I've used node.js in such an application and "version 2" was written in another language because of the GC pauses.
In my experience writing real world server programs, Node.js is faster than Go in many cases. Part of this is a lack of Go library maturity, but it's also due to the fact that V8 optimizes code at runtime based on how it's being used. This project seems to come from a naive, "interpreted slow, compiled fast" view of the world, leading to false assumptions like Go is going to be automatically faster than Node.js because Go is AOT compiled and Node is JIT compiled.