I generally prefer the girl diapers to the boy ones. (Although I'm very happy with gender-neutral diapers, too.) The problem I have with the boy designs, especially in GoodNites, is that they're just not "little" at all. On the contrary, in fact; the superhero and sports-star themes are directly at odds with the rather humbling purpose of the product. As an ABDL, though, I like the humble purpose of the product. I want to feel like a baby, or at least like an accident-prone little kid. Now, butterflies and Tinker Bell don't exactly scream "accidents" either, but they are more readily associated with childhood and littleness.
Plus: Who would you rather see in a diaper? Tinker Bell, or Iron Man?
I rest my case.
(Although I'm sure Iron Man will get at least a few votes, so maybe it's worth a poll.)