There was a time where this would have been really close for me. Then Final Fantasy XIII happened shooting FF in the foot. Then Breath of the Wild happened which raised Zelda's standing tremendously and now it's not even a contest.
FFXIII was the last straw for me... XII wasn't a bad game but it wasn't FF either. Sakaguchi and Uematsu departing the series really took its soul. As you say Zelda has maintained a level of excellence.