Subspace Emissary or World of Light?

[Super_Boom]

World of Light has a Mythra spirit appear during the final battle.

Subspace Emissary does not have a Mythra spirit appear during the final battle, or any battle to be honest.

Easy choice.

In seriousness, depends what you want out of it. Subspace had better cutscenes (as fanfictiony as they were) but the gameplay sections felt pretty lackluster, like I was just walking around half the time. World of Light had tedious sections too, but the overworld maps were really well done, had hundreds of Nintendo homages in the Spirit choices, and overall felt like more of a satisfying challenge to complete. So I'd say I prefer World of Light personally, even without taking best Blade into account.