For most things language performance is just a constant - the really hard issue is making something distributed and it's really here that Erlang shines. Being a Python programmer I know that creating a distributed application in Python is far from simple - while it's almost a trivial task in Erlang.
I was wondering about this. Is it really comparing like with like? I do not know Erlang, but I thought it had a lot of overhead from being designed for distributed apps etc.