I've been using Sublime as my Scala "IDE" for a while now - what it loses in certain 'critical' IDE features like code completion and variable extraction it gains in speed, ease of use and lack of bloat.

I agree that as far as real IDEs go, IntelliJ is the best - but that's not saying much. The rest are pretty awful. They all do many things poorly, whereas Sublime does a few things very well.