- Its not objective: It's from Typesafe. Logically they are not going to mention the negative sides of Scala
I used Scala myself and I think it is a very good approach to combining functional, imperative, object oriented and type safety in one language.
But the big downside is complexity: Scala is utterly complex, its has all the features of java. But it simplifies the object model (everything is an object), that's a good thing. But the type system? Really complex. Making compile time errors very difficult to understand.
A shift to functional style programming is happening more and more. But I think, and hope, there will be a complete paradigma shift from imperative to completely functional. This should start with universities starting with lambda calculus and functional languages to 1st year CS students.
Functional programming has the simplest execution model, is one of the best to reason about, and works very well with current multicore systems. That's why i'm spending more time on learning Clojure than learning Scala. In the end a language like lisp is much simpler but the paradigma shift is what makes it a bit difficult for those imperative programmers like me.