Here is a montage of a few different ideas I've run across over the years and combined the best parts, and don't remember at all where I got these points but they totally reflect the difference, in my opinion.
"The main differences between the two universes of DC and Marvel is a kind of inverse logic,
in that DC’s characters are more God-like but in the guise of humans, whereas Marvel characters
are more human but given God-like superpowers.
DC’s heroes are endowed with almost immutable virtue, whereas Marvel’s characters are often thrown
into the superhero position by accident and still deal with their all-too-human condition.
DC generally utilizes fictional locations for its heroes such as Metropolis (for Superman),
Gotham City (for Batman) Central City (for The Flash) and Coast City (for the Green Lantern).
On the other hand, Marvels heroes are usually fighting for cities that we know.
They’re more grounded to reality in that aspect. We see New York City, Washington, D.C.
and San Francisco threatened and destroyed, not some fantasy cities."
Stan Lee said himself he created the heroes to be exactly that from the start to be relatable.