Better is very subjective.

They both solve a lot of the same problems, but lots of people will go for Kotlin just for static typing.

Groovy 2.0 added static typing: http://www.groovy-lang.org/releasenotes/groovy-2.0.html

It added type checking ala. Hack and Typescript. It's optional, and doesn't give you the same compile-time guarantees that a language with pure static typing does.

Also, dynamic languages like Groovy take a performance hit. Static typed JVM bytecode runs faster than dynamic bytecode.

Whether either of those are relevant to your application really depends, but Kotlin definitely is going to gain some followers due to it's differences from Groovy.

I'm learning Swift right now, and really appreciate type checking.

> Groovy creator Guillaume Laforge blogged that, “an acquainted Groovy eye would immediately notice the inspiration the Swift designers took from Groovy.”

Guillaume Laforge is NOT the creator of the Groovy Language, James Strachan is. And Swift did not take inspiration from Groovy.

What else is inaccurate in the article? 6 months after it was written, Pivotal voted against Groovy's diversion into static typing and Android development by retrenching Laforge and the programmer working on it.