So... while we're looking over which of the two is 'more', let's not forget that history has already chosen the victor.
In 1504, the Florentine government formally set up a competition. Both masters were to paint great battles at the Palazzo Vecchio. On one side, Michaelangelo's
Battle of Cascina, on the other, Leonardo's
Battle of Anghiari. Both paintings were removed or painted over since (a shame, really, imagine what a sight it must have been to have both frescoes in one room).
Two years later, by 1506, the competition ended and the 'ultimate genius' was confidently chosen by the city of Florence.
The victor's prize was to decorate Rome itself. To stand before God and craft the very essence of the Vatican, shaping the future of art.
The loser resentfully left Italy, crossing the Alps. He took his most famous painting with him, where it now rests in La Louvre.