I am aligning myself with those who prefer Marvel, but think DC would win.
That's the problem with DC, all their characters are supposedly "the greatest". Marvel heroes are often flawed, and are often weaker than many of the marvel villains that they have to fight. That's what makes Marvelso interesting, outcomes are uncertain, and the characters ppossess a humanity that DC characters don't.
The only DC character that can hold my attention is Batman, but yet again, there is a character who is flawed, and often faces superior opponants, but finds a way to win.