DC is all about great stories. What DC lacks is action eye candy. That always will be Marvels thing.
DC in the last 20 years put Alan Moore, Neil Gaiman, Garth Ennis, Grant Morrison, Joe Loeb, Geoff Johns, Brian K Vaughn, David Goyer and countless others on the map as award winning authors. Marvel was so strapped for writing that everything was Bendis for a long time.
Marvel has Brubaker, and Ennis now so thats given them some quality at last. However DC is still more renowned for it's writing, but unfortunately in the comic world of big pectorials, and boobs great writing take a backseat to Marvels colorful action oriented books.
Hence marvel still dominates in sales. Just shows that no matter how brilliant an issue of Constantine is, the average person will always reach for the Uncanny Over-Xposed-Men.