With the speed comparable to C/FORTRAN and the learning curve as Python, I think Julia may have a very bright future. Currently, the visualisation packages are not so rich but on can always try matplotlib since using python in Julia is not hard.
A bit part of the AstroLib is still under progress in Julia. I am surprised that there are only three main contributors that are translating IDL/Python packages to Julia. I would like to also contribute a little once I have learned more about this language.