I have swung back and forth and honestly I love both and have major issues with both.
To me DC is both old school and yet oddly darker at times. They still have one foot firmly in golden age, and yet have had some real dark story lines for characters.
Marvel was initially the more modern one making heroes more human which appealed to me for a long time, but sometimes I like a break for moody somber tone I found too often.
In comics or source material I honestly fell out with comics because it became too complex, too expensive, too confusing and often I didn't care for changes or ideas introduced. At $3-5 an issue I like to know what is going on care about the characters.
In cartoons/animation my whole experience is 90s with a few recent films thrown in. To me DC wins, but Marvel has been solid. Batman animated series is still my favorite to go back and watch.
In films DC way back dominated, but they sat still while Marvel made tons of moves to mixed results. Once the MCU got going the gap grew despite enjoying the Nolan Batman films. I hope DC has success in coming years as I have an Ant-Man film, but still waiting on Flash to finally get one.
In video games, it really is Arkham Batman games and everything else for me. Shame as would love more quality super hero games, but most are just okay like Beenox's Spider-Man titles.
Over all it is really hard to say as I enjoy aspects of both and want both companies to succeed, but I also get really annoyed with decisions made in handling their universes and characters. Chief among them is killing characters off, bringing them back, or replacing them with less likable versions.
