Travis CI has been by far the easiest tool to integrate into this project. They really seemed to strive to keep things simple, well-documented, and easy-to-use. I only have warm fuzzies to send their way.
In the end, my
.travis.yml file is reasonably complex by Travis-standards (16 lines). I have one sbt project that deploys to two different production apps using a multi-buildpack trick, but despite my complexities, I cannot complain at all about setting up the configuration. Travis CI is a great tool and a real asset to the open source community.