Groovy has a great eclipse plugin that makes it pretty much seamless from Eclipse - it "just works" the same as if you are programming Java. Your programmers will feel right at home.
Yeah, the Groovy plugin for Eclipse is pretty decent. The "intellisense" function can be a bit slow at times, and I think there are just a few more times that it is unable to find the relevant auto-complete, as compared to working in Java. But other than those two minor nits, it mostly "just works" as you say. I'm a fan.
