I agree. I use Scala for a personal Android app. Once you get over the antbuild and proguard hurdle - agree its no walk in the park - its smooth sailing. Scala meshes well with the android libraries and is fast. Although it gets highly wonky if you need to add a library that is not a jar but instead a package.

The major downsides which are super troublesome are that it takes 2 minutes to build each time - even for trivial changes and I have to debug the old school way with messages.