Some people liked this deduplicator software.  You can visit its web page here.  “With Tidy Up! you can search for duplicate files and packages; by the owner application, content, type, creator, extension, time modified, time created, name, label, visibility and date/age. You can also search by the tag, duration and bit installments of MP3 and AAC sound files and EXIF metadata* , search the contents of the iPhoto, Aperture, iTunes, iPod databases and Mail mailboxes, and synchronize deletions with iPhoto, Mail and iTunes.”