I'll likely end up buying both, but Elder Scrolls by default of the worlds Bethesda crafts.
How I see it, many games say they have life like works with NPCs, Fallout and Elders Scrolls are in a class in their own of ACTUALLY doing this. I can trust that the team will have that type of world building were the NPCs have their own lives, wake up, go to sleep, die etc
Any other game needs to PROVE they can even do that to such a level for me to even slightly consider getting it, let alone NOT getting Elder Scrolls. As of right of right now, Elder Scrolls and Fallout simply have more solid and grounded concepts of how NPCs, towns, the world etc are crafted.