Different maps as different levels, or one single level?

Assuming my game isn’t so big that it will get unmanageable, is there a difference (rendering wise) if I choose one map per game level, or just programmatically transport the player to different sections of the same map, giving them the illusion of switching levels? I know that using different levels allows me to use level streaming and other nice things, but purely from a rendering/performance perspective, which one is better, or is there any difference?