[ffriend]

> But my ruling for libraries is anyway: use as few as possible.

And this is the point - if you want to be productive, you have to use _may_ libraries. Unfortunately, Scala's way is not to carry about compatibility, making it extremely hard to grow up large projects with a lot of dependencies. For example, we heavily use Apache Spark which targets Scala 2.10, but this makes impossible to plug in many libraries that only support Scala 2.11. The same applies to library dependencies: just yesterday we had to introduce a number of exclude rules into SBT file to reconcile Spark and HBase, because SBT was failing with cryptic messages.

> I mean slower than what?

Go, Java, Clojure, C#, Python (PyPy), Haskell? In my experience, only C++ and Scala make compilation so slow that users bother about it.