Haskell might be a bit of a bad example considering how far ahead it is compared to other languages in terms of PL features (like type-level programming). When

Haskell might be a bit of a bad example considering how far ahead it is compared to other languages in terms of PL features (like type-level programming). When compared to other imperative languages, Scala is very feature complete, and Scala also has pretty much all the features of ML-type functional languages. It's definitely at a good intersection of "useful" (all the JVM stuff) and "nice" (you can be functional or imperative, writing DSLs are super easy, etc).