Anime. I can't do both to be honest. If they do one thing with the manga and another with the anime it would drive me crazy. I also have a thing against manga spoiling things for me. It discourages me from even looking up certain characters because I do get spoilers from time to time.
EDIT: Very stupid of me to not even mention why I like anime better. The voice acting and animation really brings the story to life for me rather than just reading picture sequences.