Depends on the decade, IMO:
In the 1960’s and most of the 1970’s, the House of Ideas smoked DC’s ass.
Marvel put out the Lee-Ditko Spiderman, one of the all-time classics, and the Lee-Buscema Spidey was pretty good through the end of the Spidey vs. half his villains’ gallery over the Petrified Tablet storyline.
The Fantastic Four had that series of great stories beginning with the Frightful Four beating the FF’s collective ass, and ending with Dr. Doom stealing the Silver Surfer’s powers. In between, Ben fought Mr. Fantastic in one of the best battles Marvel ever staged, and Marvel introduced the Inhumans and Galactus.
Lee and Ditko collaborated on the best Dr. Strange ever, Steranko drew Nick Fury, the Silver Silver had a helluva run in his own title, Starlin put out Warlock, Neil Adams did a vastly underrated job on the X-Fools, the Avengers were usually good, especially with Englehardt and Shooter doing the writing, Marvel introduced Shang Chi, and Iron Man and Daredevil were usually good.
Against this, DC could field only the Legion of Super-Heroes, especially the Shooter-written issues, and the Englehardt-Marshall Rogers-Terry Austin Batman. Tho’ to be fair, Flash was usually pretty decent.
In the 1980’s, DC gave us Alan Moore and Dave Gibbons’s the Watchmen, Neill Gaiman’s Sandman, the incredible run Moore, Rick Veitch, Tottleben and Bissett had on The Swamp Thing, Brian Bolland’s Camelot 3000, and the Levitz-written Legion. George Perez did pretty good work on the first 25 or so issues of his run on Wonder Woman, the New Teen Titans was well-drawn, and Batman was pretty interesting.
Against this, Marvel could only offer Walt Simonson’s Thor and Master of Kung Fu, which Shooter was stupid enough to kill. DC wins the '80’s hands down.
Don’t know about the present, as I pretty much quit reading comics 8 years ago.