While The Elder Scrolls world isn't terrible and definitely has some very interesting lore behind it, I've felt a much stronger emotional connection to the world around me while playing the Fallouts. You're not trying to "save the world" in Fallout, because the world already ended. Instead, everyone's just trying to pick up the pieces, and you're just some random schmuck who stumbled into a position where you have to decide what the best thing is to do with those pieces. It's a much more effective draw for me. Then there's the matter of the characters that inhabit both worlds, which is an area where Fallout also beats out The Elder Scrolls. If you asked me to list off all the most memorable characters I've met in TES games, I'd probably be able to count them out with my fingers, and most of them would be on that list because they were simply entertaining (Sheogorath and M'aiq the Liar, for example). The list for Fallout characters would be absolutely massive by comparison, and consist of a decent number of more emotional, insightful, or relatable characters (like Boone, Ulysses, or the Lone Wanderer's dad) to compliment the entertaining ones.