Godzilla is the first Daikaiju I've ever seen and is still my favourite. His movies have ranged from culturally shocking, to hilarious and silly at best. He was a defining monster to the movie genre. He will never be forgotten. And to me, he really and truly is, the king of the monsters.
Leatherback is good. But I'm sure Del Toro would agree with me that Godzilla'd mop the floor with him.
Leatherback - Legendary, Del Toro
Godzilla - Toho