I always just keep a console open and compile from the command line, because IntelliJ compilation is huge waste of time. I rarely debug because that means I'd have to wait 2 minutes for IntelliJ to do it's thing before it launches.
Oh, and the test output is inconsistent. It often reports that all tests pass even when they are failing.
Other than that - and it is a huge inconvenience - IntelliJ is still awesome for Scala development. Everything else the editor is capable of easily justifies it's place in Scala development.
The issue is with IntelliJ -- when I want to run Play app from IntelliJ, not from command prompt, to get easier debug support when running the app or junit tests. Running tests from IntelliJ is more convenient than using activator shell.
Yes, I could provide -jvm-debug flag to the activator command line but this works only when fork:=false, which can't be always used.
Each Scala run inside SBT-enabled project takes >10 secs minimum to run. Every single run. SBT make is invoking the full SBT startup sequence and is unable to reuse the session. This comes from the context of using Play Framework where you can't substitute SBT with something else.
I do hope that SBT server becomes a reality at some point and IntelliJ Scala plugin is able to fully use it.