I'm probably one of the few Julia users who's NOT using it for scientific / numerical analysis / very-obscure-technical-field work. I'm just a general programmer - I'm more interested in getting data from point A to point B, processing it quickly (whether that's parsing web server logs or creating user activity graphs - a lot of the work I do is security related), and then outputting it in a way that makes sense to me. I use python but find that Julia's speed (both of execution and of development) is too good to pass up, especially for complex things. (Also, python's regex handling is horrific, and really, no general programmer is still using Perl :) )
For my use case Julia is both amazingly good and incredibly frustrating. I love writing Julia code, but the instability of some of the core libraries drives me nuts. Here's my biggest challenge: Core to any language should be a standards-based way of getting data in and out. Right now Julia's a bit of a mess in that regard. For example, Base has download(), which in turn relies on system utilities: curl, wget, or fetch, according to the docs, which also say something to the effect of "casual use only". JuliaWeb (of which I am a member) has a variety of packages with duplicate functionality, including Requests.jl and HTTPClient, but there is no settled standard yet for the underlying technology, and each package has its own set of limitations not found (or better hidden) in more mature packages in other languages. Until we figure out a way to make it easy for folks to get their data into and out of Julia, I think we're leaving potential new users "on the table", unwilling to switch because migration is just too hard, and the lack of good data transfer / network utilities is a large part of that. So this is my plea: if you're interested in helping form the basis for a great web/data transport stack in Julia, please join us in JuliaWeb. We've got a list of issues posted https://github.com/JuliaWeb/Roadmap/issues in case you feel an urge to help fix some things and develop some new things. It's pretty much a green field at this point.
