Given that Julia is not even in version 1 and has a lot less libraries than Python I don't think Julia is a serious contender in Scientific Computing today. But I am pretty sure it will be. But that wont happen over night.
I love programming Julia. It is great for doing hobby stuff and just have fun programming. There is a lot of opportunity to actually participate and make serious additions to the language or libraries because so many things don't exist yet or have not yet become finnished. To me Julia is at the moment the language that maps best to how I like to think about programming problems. It has macros like LISP, but sane syntax for doing math. I wrote a blog entry<http://assoc.tumblr.com/post/71454527084/cool-things-you-can-do-in-julia>about some of these points and on why I think Julia is more expressive and creates more readable code than Python or Ruby here<http://assoc.tumblr.com/post/71454527084/cool-things-you-can-do-in-julia> .
