My first impression of Kotlin is a simpler Scala retaining the core principle: let the compiler do more, the programmer less. Heavy amounts of inference where it is useful, much shared syntax.
Good luck, JetBrains!
UPDATE: I missed this wiki page my first pass through: Comparison to Scala. The page has interesting comments as well.
UPDATE: Stephen Colebourne expresses a lot of my thoughts better than I do on Kotlin.