That's not to make a dig at Scala. It's way better than Java. It's also really complicated, and the need for JVM compatibility is a big part of that. Then you have the compile speed issues, the problematic tool chain, and the fact that average Java programmers, given Scala, will create unmaintainable nightmares.
I'd use Scala over Haskell when I wanted JVM interoperability, or if I needed to train people up quickly. For a "bet the whole farm" play, existing programmer familiarity actually matters a bit less-- "the whole farm" is rarely bet on a one-month project-- and I'd pick Haskell first.
Did you ever use Haskell? Those issues are far worse in Haskell than in Scala.
You just hear more people complaining about Scala, because it is used, while Haskell projects are usually not developed and maintained anymore after the author finishes his PhD.
I've used both, if anything Haskell is a little faster.
> You just hear more people complaining about Scala, because it is used, while Haskell projects are usually not developed and maintained anymore after the author finishes his PhD.
FUD. This is simply not true.
The first compile might take a bit, but after that all changes are usually incrementally compiled in less than a second.