Nightmare. The 1st track off of Avenged Sevenfold's album, Nightmare. Pretty fun song. One of the best A7X DLC songs available for download on Rock Band.
Guitar- Extremely (emphasis on extremely) fun song! The solo is fun, and easy, and it's just an enjoyable song, not too easy, not impossible.
Bass- Equally as fun as guitar. After the beginning before the first Chorus, the bass part sorta dies out. Not as fun as it was when the song started.
Drums- Not easy. Period. The intro is hard, and once the solo finishes up, it's just flat out impossible with one bass pedal. The Chorus is nice and easy.
Vocals- Simple. Any A7X fan will know how to do this and get 100% easily every time.