[cess11]

Not sure how the 'best products' constraint is supposed to be interpreted, but Elixir is a more flexible tool for developers than Golang. It has a decent REPL, can be used for scripting, and so on.

I haven't used Golang for things like binary protocols so I can't really compare, but Elixir or Erlang would be a good fit since they're very good for expressing grammars and fundamentally treat strings as byte sequences.

If pattern matching helps you express your problem domain succinctly they're also a good fit. Same goes for macros. My impression is that Golang commonly requires quite verbose or complex code compared to Elixir.

I expect raw number crunching performance to be better in Golang, but BEAM processes are very lightweight so it might win on either performance or developer ergonomics if the task can be solved in parallel.