Haskell can be annoying to work with in the beginning, since the slick quicksort examples don't really explain why you'd want to use it to write something real.

Haskell can be annoying to work with in the beginning, since the slick quicksort examples don't really explain why you'd want to use it to write something real. But then your project grows bigger, and the type system maintains sanity in a way you don't otherwise see. Other languages usually use tons of unit tests everywhere to enable refactoring, but then they bog you down if you really need to change something. I guess it has problems with records, space leaks, and deployment to old machines. Maybe ML or F# are just as good for this purpose; I haven't really used them.