Presumably appearance doesn't grant you the potential immortality that being able to change your age at will grants you. It does allow you to be whoever you want to be, presumably within the limits of human appearance irrespective of outward presenting gender and whatnot, which begs the question of anatomy. I think the idea of having a potential for immortality is kind of scary, so I'd probably go for appearance.
Would you prefer to be the most talented person in history in a given hobby but an absolute pariah in the community or the most mediocre, but most beloved person in that community?