I hate them both, but you really can't compare the two. One is a movie series, and the other a famous pop-singer. While they are both terrible in my opinion, they aren't even in the same industry
I think Justin Bieber is worse, but it's only due to the fact that he sabotages an art that is more valuable to me.
Either way, they're both a terrible hindrance to humanity's well-being, even though I abhor more artists like lady gaga to be teaching young girls to be impudent sluts.