I think Clojure and ClojureScript are really very nice, and a good contender to Scala if you like dynamic type systems. I think the biggest potential competito

I think Clojure and ClojureScript are really very nice, and a good contender to Scala if you like dynamic type systems. I think the biggest potential competitor to Scala may be Swift, now that it is open source. If it becomes as multi-platform as Scala is, and good back-end libraries become available, then Apple's support may be very hard to compete against. There were even rumours that Google was considering using it for Android. It is nice to see that Scala will soon be available for mobile development too. In a short time, there will be a nice overlap of platforms supported and language features, which will provide for interesting competition.