Japanese, in the majority of cases. However DBZ is prlly better watched in english and certain Japnese voice actors seem to do a lot of different parts (like english) so sometimes a character is ruined for me if he's the voice of another character.
japanese
because their voice actors are really talented and go through auditions, the english voice actors seem to be picked up off the street lol and just sound terrible most of the time
Well actually ots a very competative thing for both