We played around with SoT and mez and what it seemed to us was that,
whichever ends first will break the mez. Song and spell will both stick,
but as soon as one duration expires, both expire... I found that pretty
weird... I have no idea why they dont let the enchanter mez just
overwrite the bard mez, that would really give bards something to do on
raids, as we could spot mez a big pull while the enchanters are locking down
all the mobs. Not to mention let us save an enchanter's bacon when they get
agroed...

Elfson Allegro <The Circle of Eternity> 54 Veeshan
(I know you're shaking in your boots, Sart)