Well, let me do a quick comparison between them before I make my decision.
First off, games they've made and/or worked on for Nintendo.
-Super Smash Bros. Brawl
-Disaster: Day of Crisis
-Baten Kaitos Origins
-The Legend of Zelda: Skyward Sword
-Animal Crossing: New Leaf
-The Legend of Zelda: A Link Between Worlds
-Animal Crossing: Happy Home Designer
-Xenoblade Chronicles X
-The Legend of Zelda: Breath of The Wild
-Xenoblade Chronicles 2
-Xenoblade Chronicles 2: Torna-The Golden Country
-Animal Crossing: New Horizons
-Xenoblade Chronicles Definitive Edition
Most of those games are held in high regard, even some of the ones in which Monolith Soft was NOT the lead developer.
-Metroid Prime 2
-Metroid Prime 3
-Metroid Prime Trilogy
-Donkey Kong Country Returns
-Mario Kart 7
-Donkey Kong Country: Tropical Freeze
All wonderful games, but too few and far between as of late.
My vote goes to Monolith Soft, although I would like to see them as lead developer on something that's not an open-world adventure game or JRPG, and this is coming from someone who loves Breath of The Wild and Xenoblade Chronicles 2.