I think it's strictly worse than Ceylon - less mature, less featureful, and a lot less well designed.[1] And JetBrains have a bad habit of advertising features long before they're actually implemented, as well as talking up Kotlin for about a year and a half before it had any kind of stable release.

[1] And frankly if there's nothing it can do that Scala can't and the design isn't any cleaner than Scala (arguable, but I feel Kotlin is very ad-hoc and will look worse than Scala by the time it reaches the same age) then I'll just stick with Scala - whereas Ceylon can make at least some case for migrating from Scala.