Personal preference is another matter, of course. It's hard enough to quantify the value of a single creative work, so trying to quantify the value of a sprawling, decades-old, media-spanning, complex and unwieldy mass of creative works resulting from the input of thousands of people whose only common denominator is the company that owns the copyright is an impossible task. Add to that the fact that Marvel and DC properties have shared writers, artists, directors, actors and other talent, and the argument as to whether Marvel or DC is 'better' becomes more futile than ever.
