In the era of Superhero movies DC had a head start, but the unrivaled king of the superhero box office is Marvel. When Joss Whedon was asked about Marvel's perceived superiority here's what he said -
I don’t think I would say that. I think that would be a little presumptuous of me. I think that both studios have kind of different agendas, different ways of approaching the superhero genre, and the ethos of the thing, and the esthetic. They go very dark and serious and sometimes it works amazingly, and Marvel tends to be a little lighter. Both have movies that I adore, and both have movies that I’m like… [pained expression]. Including bits of my own. I would not want them to do what Marvel does. I like what they do when they get it right. When you get a Heath Ledger, and Batman Begins, and those things that really grip you. That’s something nobody else is doing, and I like it. I want them to do what they’re doing.
Joss Whedon is absolutely correct when he talks about the seriousness of DC movies. But, that's not the only thing different about DC, they also have massive budgets. Even when they're not very good, DC goes all-out with their superhero movies, spending like crazy and allowing directors free reign over their characters. Marvel's approach has been to suss out talented, low-budget filmmakers and let them play in the Marvel sandbox.