I've worked with Xtend. It's a nice language but it's just a bit too unopinionated. E.g. you can import java static methods as extension methods (or not), you can even import instance methods as extension methods using a special annotation (or not). the implicit lambda paramter can also be used as implicit receiver. You can omit the return keyword (or not) even in functions with bodies.
All in all, there are too many ways to do the same thing.