I once drank the Scala cool-aid as well. Even wrote an enthusiastic article about it [1]. Since then, my enthusiasm has been replaced by disappointment: the JVM interop is a lie, as Java libraries often are a bad fit, people won't have time to write the extensive wrapper code needed to hide it, and as a result ugliness starts permeating your codebase - yes, bad, but that's how teams under time pressure work; the multi-paradigm-and-widening (back in 2009, Scala was a smaller language) is one big headache - everyone has an opinion of how you should write code in Scala, so inevitably you spend a lot of time debating features you should or shouldn't use in your teams (instead of writing code. In Elixir, we never have to debate paradigms, we write code); sbt is a sorry mess - no-one understands it and it's slow.

I still think it's a very well designed language, the choice of the JVM+Java ecosystem as the target just has bogged it down with legacy crap like everything else on that environment and the designers should start to make some choices instead of offloading that on every single development team in the world. I think that "single-paradigm" is one of the reason that simple languages that get shit done, like Golang and Elixir, are so successful these days.

Were I bound to the JVM, I'd still give it a good look (not sold on Clojure or Kotlin yet and it _is_ nicer and less frustrating than Maven+Java if you keep it simple); I'm just not married to the JVM so can freely consider other options.

[1] http://www.artima.com/weblogs/viewpost.jsp?thread=260478