Erlang has a slightly different but largely equivalent model, but the other alternatives you mention lack Go's channels and/or the select construct which is one of the greatest things about the language.
When I found that Stackless Python didn't have a way to read/write on multiple channels at once I was quite shocked.
It also looks that "select" statement could be done in a combinator library way.
The power of Haskell (or of any proper modern language) isn't in the language itself, it's in the number of things you can express as a library, on top of the language.
