Well lets see there are huge inconsistency between both. Superheroes like DC and Marvel has different universe/alternate version of each heroes while Manga series tends to stick with one version and end it with that. Superheroes are written by a lot of different writers, some makes the heroes op for no reason, some degrades them, some changes them entirely. Manga are written/created by one sole writer, the person that created that manga. Manga has more type of genre while Superheroes are stuck on a couple. Bottom line they're both too different to pick one. In my bias opinion I choose Manga.