Julia's compiled code might be super fast, but developing (or, God forbid, doing any sort of analysis) is painful because of how brutally slow the REPL/interactive environment is. Pretty much every little snippet of code you'll want to test as you write Julia feels like it takes _forever_ to run. I don't know if there's a solution for this while retaining the compiled run-time performance. I'm new to Julia (from R and Python), but I find the slowness/sluggishness of REPL to be nearly a deal breaker for me. It feels like the web back in the 1990s when you'd click a button and wait, and then click another button (or link) and wait, etc.
