Last week, we migrated the entire www.optaplanner.org website (1399 files) to build with Java and Maven, instead of Ruby and Rake. On the face of it, nothing changed. But in the sources, for our team of Java developers, it is a game-changer.
Our java team can now contribute to the website easily. Within hours of completing the migration, there was already a commit of one of our developers who would rather not touch the previous source code with a ten-foot pole.