I'm about to release an app (will probably publish a beta today - https://invotes.com), and it actually works quite well.
The compile times are probably a bit slower than a standard java project, but not bad - something like 5-30 seconds depending on if it's a full rebuild.
I use android-sdk-plugin with SBT along with Scaloid. Wrestling with proguard to hide appropriate warnings can be a little bit of a pain, but even with no prior Android knowledge I was able to figure everything out.
Everything works as expected. There are a few minor issues where Java expects null and that's not normal Scala style, but other than that, nothing important to speak of. My binary builds to 4-5mb.
I've written some basic android apps for my own use in Scala. There's a bit of a mismatch with the android API (which is very much oriented towards traditional-Java mutable objects and one-thread-per-thing style) but I still find it nicer to work in Scala.
I spoken to many that have made Android apps with Scala but none that have pushed them to the appstore as the final binary is always quite big even for simple apps.
I wouldn't say that's true. I have an app written in Scala [1], and the apk is just 4 MB. Sure, that's more than a comparable Java app, but many apps reach 20+ MB due to graphics anyway.
