I'll say DBZ at the moment. I caught it again before Teen Titans last night, and my brain melted. I see it as turgid and boring, hardly any good characterization, and not much of a diverse cast (hardly any women).
But mostly, it's the time issues. Five episodes to do ten minutes of their time? Dear God, it's a wonder anything got done at all.
So yeah, and the successor GT is worse. At least DBZ had Scott McNeil and Ian Corlett to amuse over. Until they dubbed over them. Headdesk. At least they're being consistent. But overdubbing good VAing to have bad to be a constant? Not a good idea.
Anyway, that's my choice. At least you can say DBZ are all plot episodes but they never go anywhere, so why bother?