There are mainly huge instanced maps, that in some places has a few seconds pause to go through doors (for example going into a minidungeon), but for the most part the huge instanced areas are really big so you don't go through loading screens very often while leveling. (Instance isn't really the right word with the help of Cheap Blade And Soul Gold, here, like the guy above me mentioned 'zone', seems more appropriate term)
Unless you're deliberately going back and forth exiting and entering a large town that has it's own map and loading screens, you don't see a lot of loading screens.
Leaving a mini-explorable dungeon area has a loading screen, but going into it just has the couple second pause loading thing (at least in my experience).
I guess it's just that it is instanced, but the instances are so big [and often filled with players (unless in a personal quest or explorable dungeon)], that you just don't notice that it's instanced, too much
It's not a game that has one town with personal maps where you fight monsters alone with Blade & Soul Gold. It's more like: huge world filled with other players that sometimes go through loading screens to get to next huge map (and the mini-dungeon type areas you can go alone).
Best comparison like the others said that it's like gw2 or wildstar?, which is kind of the opposite of vindictus or dragon nest style maps