SpecsUpdate
Pros
Pro Fast and smart contextual assistance
Uses a fast indexing technique to provide contextual hints (auto-completion, available object members, import suggestions). On-the-fly code analysis to detect errors and propose refactorization.
Pro Clear and detailed documentation
The documentation is exhaustive, easy to navigate and clearly worded.
Pro Community edition is open source
The community version is open source and works perfectly with Scala.
Cons
Con Performance
Tends to slow down, sometimes to the point that keystrokes don't register for a few seconds, especially when making heavy use of implicits.
Con Lacks Good Support for Individual Files or Scripts
You can't really work with files outside of an sbt or maven project with IDEA. Sometimes you'd just like to write a single-file command-line tool in Scala, but you'll have to reach for a different editor when you do.
Con Inspection Can Be Wrong
Sometimes the in-editor type checker incorrectly marks code as incorrect, despite the code compiling and running.
