I'd say the distinction we have over other services is that we offer a completely transparent solution - all our translators are tested and rated to ensure they meet a consistent quality standard, so you don't have to pick and choose them as you do with others.
So you can literally treat us like a machine, which hasn't been true when I've tested those other services (I got bombarded with emails from translators asking me to pick them for my jobs, which really annoyed me).
We think that's pretty compelling for developers, and makes us a much more scalable solution :)