I like that it is very simple to use, has many features out-of-the box (like authentication), support multiple languages/frameworks at once etc., so you can focus mostly on your app logic rather than configuring servers or database connections - all this stuff comes with JDBC drivers by default! It's also open source which makes me feel more confident about its security compared to commercial products from other vendors who are usually closed sources in my experience. The UI could be improved though; maybe they should make some kind of dashboard where one would see how much time was spent coding vs testing & debugging? Maybe then people will actually do their jobs instead of just waiting until something breaks ;) We're using jMix as an API gateway between our backend services written mainly in Scala Play Framework 2 + Akka Actors / Http Services running over Apache2 webserver.