The Python runtime is relatively poor (slow and limited by the GIL) but the language is extremely popular [1].
Is there any other language which is a "best of both"?
This constrains the space quite a bit. Languages significantly less popular than Python are excluded by definition [1]; languages subscribing to very opinionated design decisions or too low-level (like C) are also excluded by definition.
This only leaves Java, C++, Python itself, and Javascript. If you run Python on a JIT runtime like PyPy [2], you'll probably achieve significant speedup.
Erlang, Elixir, Scala, Clojure, languages that also have good approaches towards concurrency are not very popular in the greater scheme of things.
[1] the TIOBE index is an imperfect measure of popularity, but let's use it here -- http://www.tiobe.com/tiobe_index
So, thank you for listing some less-popular languages as well. Unfortunately, of all 8 languages listed in your post, is C++ the only one which can produce standalone binaries and thus match the easy deployment of Go?