mdb was inspired by Apple's iTunes. I loved the flexible access to my CD collection, but was repeatedly frustrated by the program's limitations. Central to these is the long delay in copying a large number of tracks. In mdb you can quickly copy a playlist by pressing the copy button. You can easily build complex playlists by selecting songs with different search keys and then copying and merging the results.
mdb is more narrowly focused than iTunes. It aims to provide flexible and intuitive access to ogg and mp3 audio files for creating playlists.
mdb is not an audio player, but it can interface with some audio players. This avoids the patents on mp3 audio decoders. This is a problem for free software in countries that recognize patents on software and algorithms.