Yeah, that's definitely an issue. The Scala auto-complete is not very responsive, which makes the whole IDE experience with Scala pretty undesirable, sadly. I've been using IDEA with Java in the last ~2 months and it was perfectly smooth all the time. I guess Scala is a lot more complex as a language than Java, which makes parsing it on the fly much harder.

One thing I noticed about the Kotlin design and design discussions is that "that wouldn't be auto completable fast" comes up quite often. I had never thought about it before but it makes sense that language design choices can impact the speed of an IDE. I am starting to think that it also makes a lot of sense for language designers to have IDE development experience. I wish they'd hurry up and release a stable Kotlin.

It would be pretty sad if code completion efficiency became a reason to compromise on other areas of a language.

Why? They're just tools. Code completion is probably more important than a lot of the rather minor syntax sugar features in many languages.

I don't know how long ago you tried the scala plugin. But I had the same bug when writing strings. What ultimately fixed it was disabling i18n support in the scala plugin preferences. I haven't had a single freeze/stutter since.

I take it you mean the actually "Ii8n for Java" Plugin?

Scala and Play support is already vastly ahead of where it was just 6 months ago, but there's definitely more room for improvement. The overall intelligence of the IDE is still sorely lacking versus what you get for, say, Java. I'd love to see a lot more support for intelligent editing of SBT files, more intuitive ways of finding usages of instances and types, working with implicits, and refactorings that align with Scala's abstractions. It seems like such a powerful language should have an IDE that gives you more ability to access those features.

Also, I find the code style settings to be extremely difficult to tweak, in large part due to poor browsability and also because you can't actually see them applied to the example code next to the settings editor.

I haven't used the play plugin that much, but I've been very happy with the Scala plugin. In fact it's the only reason I switched to intellij. The only annoying bug I've encountered is bogus error notifications in Java code due to the ide ignoring Scala throws annotations on methods that java is calling.

I reported a series of bugs about the Java / Play plugin a couple weeks back. The support guy did some investigation and filed a few internal tickets...so they're working on it.

Agreed. In the meantime, I've switched to Ensime. Takes some getting used to but it's very nice.

Hmmm, I never had such a problem with Scala and Idea. How big are the projects you're working on? Maybe your computer is just slow.