I tried to install the Groovy plugins on a default Eclipse installation and never got the same result I got on the bloated default GGTS installation. But even with GGTS I had a mediocre experience at best. I tried the commercial version of IntelliJ two years ago and it was okay, but still lacking compared to the Java autocompletition. I'm really happy that the situation is better now.
As I use Groovy more of a host for DSLs (like Gradle or Spock), I hope tooling for this areas will improve. In my eyes, this is Groovy's sweet spot.
