last I tried it wasn't really usable. I moved to intelliJ (or just emacs) for the most part. IntelliJ support is quite good (although it does tend to freeze up for a few seconds everynow and then, getting better).

Regardless of what people think about eclipse, it is kind of a default choice for a lot of the mainstream, so I am guessing a lot of people would be interested in quality scala support.

Would love to know what state this is in, but I just don't have time to check myself.