It’s quite easy to use Gradle with Scala.
We did it for a long time (a mixed team of Java, Groovy and Scala developers) and have been quite happy with it.
Most things work quite well out of the box.

More about Gradle with Scala:
http://www.gradle.org/docs/current/userguide/scala_plugin.html

There are some problems/downfalls though:

• Mixed code compilation when depending on Scala code from Java in mixed code projects. (Some configuration and it will work, but not out of the box)
• More configuration for Scala-specific tools needed than with sbt
• Integration of some Scala tools like Scalastyle or scct is not possible yet
• no sbt console (Gradle console has not been working properly since the last time I checked)
• adding the Scala version number to artifacts has to be added manually each time (no %% as in sbt)