Although "Fashion!" is a good song, it's one song that doesn't reflect the talents of the above producers. Also, if I were to choose another, it would highlight a lot of faults in Gaga's music as most others have been heavily involved with her albums.
What is one with some of you? RedOne gave us Poker Face, Bad Romance, Judas, and plenty more good songs. The worst I'd have to say is David Guetta or will.i.am. Fashion! sucks.