1. A method of synchronizing a plurality of media content items between a first device and a second device, the method comprising: determining an inclusion set of media content items to be included on the first device after synchronization from the second device; intersecting the inclusion set with a set of media content items already on the first device to form a candidate set of media content items; comparing instance attributes of media content items having two or more instances in the candidate set of media content items in forming a final set of preferred media content items; excluding from the final set of preferred media content items any media content items with corresponding preferred instances already on the first device; and transferring the final set of preferred media content items to the first device.