It would be interesting to compare it to Nim, which is also a very convenient and very performant language.
Nim has no REPL iirc, so that is a deal breaker for most interactive work IMO. There are some data science libraries coming out (maybe arraymancer), but nothing I know of in the numerical computing arena. Nim can compile to C or C++, so I assume FFI is easy, but it's still a lot of work if you aren't familiar with C. Python has all of that handled for you with certain distributions.
It does have a REPL called inim. It seems OK, but I'm not sure how it compares to python/julia if you're a REPL power user.
It's much rougher IMO. It has no autocompletion yet [0], and you cannot copy-and-paste code in it like IPython and Julia's REPL, as it does not respect the original indentation. (Tried to copy-and-paste the first example in Nim's webpage [1] and it failed because it inserted indentation at wrong places.) For the record, IPython has the `%paste` command, and Julia's REPL automatically detects when code is being pasted (this would however be less relevant, since Julia's language is not indent-based).
I am not sure if it supports plotting libraries à la matplotlib, however. If it has this capability, it might be still interesting in its present state.