Manga. Because when the anime success hits, it's the only way to see the story properly (Like in Berserk). The anime can also catch up to the manga pretty easily, so either you'll be left with filler episodes (generally a bad thing, since it detracts from the overall storyline) or you'll have to wait for multiple seasons, or (worse) both. Though I do agree that some action scenes in manga tend to look messy, take Trigun, for example. Maybe it's intentional (so as to convey the chaos) but I can't follow the action in it when reading. Or maybe I've just been spoiled by THE GREATEST MANGA OF ALL TIME that is Berserk.