Magic Cutter is an MP3 splitting program that has a few editing and automated functions.
If you have ever digitized a vinyl record or a CD with cue points, you'll know that you have to cut your recording into separate tracks. Magic Cutter is designed for this kind of operation.
Using Magic Cutter is pretty simple. MP3 files can be dragged into the interface, and you can add track splits manually, using a corresponding CUE file, letting the app search for silences, or cutting the track by size or length of time. Manual cutting still seems to work better cutting by silence, as it's easy to see breaks in recordings using the MP3's wave form.
Magic Cutter is a pretty good tool for cutting MP3s, but it's hard to recommend as there are other ways of doing the same thing. Audacity is a much better all round audio editor, and can also be used for cutting MP3s.
Magic Cutter is a functional MP3 Cutter, but beyond the attractive interface it's nothing special.