Marvel in comics are a lot more serious and dark as many people think. And DC is EVEN MORE SERIOUS AND DARK (and they are doing some big changes about taking peoples live, I mean, Superman killed about 100 peoples in a recent comic)
There's a bit of mixing of cities in regards to DC Comics locations. Best I can pin for a location is a quote from Frank Miller saying "Metropolis is New York in the daytime; Gotham is New York at night." But yeah, Metropolis is majorly based on NYC, Gotham is mostly Chicago.
This is more based on the comics. The DC movies are never good representations of the source material. I mean, have you SEEN what they did to me in "Batman and Robin"?!
Hero in city with real name = Marvel
Hero in city with fake name = DC.