I prefer oil cupcakes. From previous experience, oil cupcakes have a heavier crumb while butter cupcakes tend to have a finer, fluffier, more airy crumb. Oil brings out the best in the sugar. Also by the second day oil cupcakes are more moist and delicious while the butter cupcakes tend to dry out. However I do love the butter flavor, so I came up with a solution.
https://theboatgalley.com/changing-pan-size/