I have released version 0.5.0 of MongoEMF. MongoEMF is a bridge between MongoDB and the Eclipse Modeling Framework making it very easy to store and retrieve instances of EMF objects in MongoDB. This version includes the ability to provide custom data type converters for storing non-native attribute values as a native type in MongoDB. For example, you can now store a Calendar as a long. The code was also refactored into a builder pattern, giving you the ability to completely customize how objects are serialized and deserialized in the database. For a complete list of new features, please see the Release Notes. I have also made some progress on a User Guide. If you have any interest in contributing to this project, please contact me.