Groovy Callout in SOA Suite

I was musing about using Groovy to implement custom logic in SOA Suite.
I stumbled on this post covering Groovy with OSB.... interesting!

I have seen a gain of at least 300% in the mass of code produced with Groovy vs Java, so I am planning to use Groovy more often in future....

I am trying to build "complex" validation logic in Oracle Business Rules, surely you can do interesting stuff with this tool, but there is a learning curve and I am not sure how intuitive the code will be...