Joystiq got a chance to put their hands on DC Universe Online at the NYCC and offers us a preview based on the experience.
Crackdown came to mind as we took our first turns around, up and over the city blocks. Specifically, the verticality of the environment was reminiscent of Realtime Worlds' super-cop sandbox. It seems that most, if not all characters will be able to access and do battle in the high reaches of the city, as speedsters can race against gravity, acrobats can continuously jump and grapple up buildings, and those blessed with flight ... well, just fly. Perched on top of a skyscraper, we got a clear view of DCUO's respectable draw distance (Metropolis is not marred by much smog, apparently) and a sense of the map's scope. The district we were playing in -- and never felt compelled to venture out of -- was supposedly just one-eighth of the total size of the city that stretched out into the unseen distance -- and that doesn't include unconfirmed "adventure areas" within the cities surrounding boroughs. (Reality check: One can't move seamlessly beyond the borders of a game map, including up into outer space.)
Admittedly, when we weren't taking in the sights, we were spending a lot of time on the move. Read: fleeing. (When we're finally able to build our own character, we'll likely opt for superhuman speed; though, the acrobats have an effective mid-air dash, useful for losing those pesky, lesser NPCs.) Our cowardice was not the game's fault, but our own. Once we realized that we were in control of a ranged character (three "KOs" later), we responded by getting out of folks' faces -- like really out of their faces. We should note that the punishment for "death" seems rather insignificant; we were subjected to about a six-second-respawn wait, at which point we arose from the exact position we had fallen on. SOE claims that instances will be time-based, and that getting KOed limits your and your team's ability to complete objectives.