Do modern-day Buddhists take "Mara The Evil One" literally? I find that a good number of believing Christians and Muslims think that Satan literally exists and is a very real actor in the real world.

Is "Mara the Evil One, the Tempter" a rhetoric device in Buddhist tales -- a personification to enable the construction of a certain kind of parable? 

Or is "Mara" understood by contemporary Buddhists as an evil being who actually exists in the physical plane that we inhabit?
Of course, I can't speak for all modern-day Buddhists, but for myself, those that I have learned from, and those that I have known, we believe that Mara is the metaphorical personification of the forces that oppose enlightenment. I've not met any Buddhist who believes that Mara is a literal personal being.