Comment by mightybyte

Haskell gives you quite a powerful set of tools for constraining and reasoning about your program's behavior. For instance, its ability to define pure functions and control side effects is a very powerful tool for preventing certain classes of bugs. Dereferencing invalid pointer locations and out of bounds array lookups are large classes of bugs in mainstream languages that Haskell basically eliminates entirely. It's not at all the same thing as what you get from the type systems in languages like Java, C++, etc. You really have to try it to appreciate it.