I think what's funny with this pair is they're actually pretty similar. Usually when I compare covers, there's not much similarity. Here, though, we've got a number of aspects: a close up of a girl with a serious expression, some extreme hairology, an all caps title, and a blue based background.
Of the two, I'd have to pick US as my favorite. I just love how the hair has turned seamlessly digital. That's some great techniques.
Who's your winner?