The extra cover is extra slipcase, with the imprint of a band member of One Direction (Harry Styles from here).
The CD is inside the already known 'Take Me Home' album. It differs in any way from the album, which you can buy without slipcase.
For anyone who has a very specific favorite among the 1D guys the extra edition with slipcase is really a nice touch and highly recommended (as it takes the price nothing to the normal version).
The music can I put all my heart, not just 1D fans. :-)
From me 5 stars - for the music and the idea of customization! A nice gimmick for fans! :-)