If you are using stock Ford rotors they are notorious for being soft, on our last 5 vehicles they are needed replaced at very low mileage..around 30K miles.
On the SHO I used EBC slotted/dimpled rotors and Redstuff pads and they are working great. I think it is more a function of the soft Ford/ Motorcraft rotors...I would never recommend using Ford rotors, they just don't stand up to today's harder pads, especially ceramic type pads.