Edit: Title asks for downsides (but it seems like tue kind of title that might be changed)
Disclaimer: I really like Julia, and loving it for some numerical stuff right now. That said...
Potential downsides:
- Very new, standard libs are still in flux
- Matlab-like syntax, which I have mixed feelings on
- Clustered parallelism uses ssh for transport, which I find slow (vs MPI)
- 1-based array indices (for Matlab and Fortran familiarity)