I'm kind of wondering whether Go is not already eating into Erlang (and Scala). I am not an expert, but I understand that Go is not at par with Erlang today, but I am wondering about a 3-year bet for a startup.
Advantages over Go:
1. Reliability (OTP, supervisor, pre-emptive scheduling)
2. Clean code (error handling, higher order functions)
3. Far superior package management
Advantages over Erlang:
1. Extensible (Macros)
2. Familiar syntax for Rails developers
That being said, Go definitely has the advantage when it comes to marketing/hype (Google, Unix daddy etc), which as you can judge by the success of Node and Mongo, sadly trumps technical merit even in the tech community.
Go can try to reach parity with Erlang one day...but Elixir already is Erlang...That combined with the fact that Elixir's package management already feels light years ahead of Go's disaster and I think it's a winner. I'm sure I'm wrong and the flames of Go lovers will engulf me in the responses, so take this with a mountain of salt.
I may be short sighted, but I seeing the ecosystem around Go to be much more ... accelerated than Erlang.