The Madison style Doctoral gown will have a gathered cuff sleeve. When you raise your hand for accepting (or giving!) a diploma, the cuffed sleeve will be visible. Overall, this style of gown is more ornate, with extra pleats (extra fabric), and a slit at the waistline for easy reach into your pockets beneath your gown. This style of gown is more expensive, but it more common because of the pocket and the cuffed sleeve.
The Jefferson style gown has a loose bell sleeve. Visually, when your hands are down, the gowns will be very similar, but the Jefferson features less fabric overall and is a little lighter weight.