In 1938, Superman, created by Jerry Siegel and Joe Shuster, first appeared in the pages of Action Comics #1. Action Comics #1 was published by National Allied Publications which would go on to become DC Comics. The debut of this issue was the inception of the superhero in the traditional sense. In 1939, Timely Publications published Marvel Comics #1 which featured Namor, The Sub-Mariner. Timely Publications would take on the namesake of this series and Namor would go down in history as Marvel's first superhero. Since then, Marvel and DC have become the two dominant companies in the comic book industry, prevailing over all other competitors. As such, the two exist in a state of constant competition; think Coca-Cola and Pepsi. So which one is the greater of the two? The subject has been a source of contention among comic book lovers for decades.
The question calls into consideration many factors and preferences and thus will never have a definitive answer. But, as someone well-versed in comic book lore, I would put Marvel forward as the better company. The reason being that Marvel in several instances has demonstrated a creative vision that has allowed for all-around better storytelling. Marvel's 1961 publication of Fantastic Four #1 in response to DC's Justice League marked the company's entrance into the "Silver Age" of comic books. This would act as the unofficial beginning to what would become known as the Marvel Universe. In the years that followed Marvel would roll out a line of now iconic heroes including, the Hulk, Iron-Man, the X-Men and, of course, Spider-Man. These characters and their stories would invoke the spirit of the times, their origins reflecting the realities and concerns of the Cold War. Many characters (Spider-Man and the Hulk for example) would gain their powers as a result of radiation, speaking to the fear and curiosity of nuclear fallout out during the Cold War's most tense years. In the original story, Tony Stark first constructed his suit after being injured in the booby-trap strewn jungles of Vietnam. Marvel's stories would also benefit immensely from the thoroughly developed alter egos of its characters. Thanks to visionary writers, the readers would care as much about the personal lives of the characters as they would their heroic exploits. Consider how much one knows about Peter Parker and Bruce Banner compared to Diana Prince and Barry Allen. Those are Wonder Woman and the Flash respectively. I needn't identify the former two.
What would further distinguish Marvel was that nearly all of its major heroes operated out of New York City as opposed to DC whose major heroes operated out of various fictional cities. This would give Marvel's stories a sense of realism the likes of which DC has not managed to capture to this day. Moreover, that Marvel's heroes shared a locale allowed for fluid interaction between its characters. Solo titles would regularly feature guest appearances by other heroes. For example, Spider-Man, in one of his early issues, would actually try to join the Fantastic Four leading to a misunderstanding and subsequent battle between him and the team. DC's characters did interact with one another, though not in as consistent or substantial a way. While DC would eventually catch up, it was this element that gave Marvel the edge over their rival in the sixties.
Jump forward about five decades and DC has again come late to the party. In 2008 Marvel Studios released Iron Man. This would be the first installment of the Marvel Cinematic Universe. Not an individual franchise, the MCU would act like the comic Marvel Universe as a conglomerate of solo and crossover titles existing in a shared world. Marvel would release subsequent solo films such as Thor and Captain America: The First Avenger as well as a direct sequel, Iron Man 2, all culminating in 2012's The Avengers. Using the same formula as they used in the sixties, Marvel constructed a shared cinematic universe allowing for seamless interaction between the characters existing within. They haven't stopped. Since 2008 Marvel has expanded the Marvel Cinematic Universe to the small screen with Agents of S.H.I.E.L.D and Agent Carter as well as five upcoming Netflix exclusive titles including Daredevil.
In 2013 Warner Brothers, which owns DC, released Man of Steel. This film would act as the first installment of DC's own cinematic universe. By the time the movie was released, however, the Marvel Cinematic Universe was already seven films strong. By the time DC's next installment, Batman v Superman: Dawn of Justice, is released on March 25, 2016 the Marvel Cinematic Universe will be twelve films in, not even considering the various television series. Just as in the sixties, Marvel's visionary and comprehensive approach to storytelling has given them the advantage over their principal competitor. It is important to note, though, that DC is experiencing a fair amount of success on television with shows such as Gotham, The Flash, and Arrow, the latter two sharing a universe.
Questions still remain concerning DC's approach. Had DC pursued a shared film universe earlier, would we have gotten the quality of Batman films that we saw in Chris Nolan's prolific trilogy? We don't know. What we do know is that the success of Marvel's approach to filmmaking, which is both dynamic and formulaic, has allowed them the creative liberty to explore their lesser known properties on the large screen. In the near future we will see movies featuring Ant-Man, Dr. Strange, Captain Marvel and Black Panther, characters more casual fans may never have heard of.
It remains to be seen whether or not DC's attempt at a shared cinematic universe will succeed to the same degree as their rival's. For the moment, Marvel dominates this new superhero renaissance and I imagine they will continue to do so into the future. 'Nuff said, true believers.