I'm pretty sure I (somehow) had never even heard of this Poe story before now. (Which is weird because I have no less than 4 complete works plus at least one smaller volume of stories.) This gave me serious Fight Club vibes, but in a creepier way. I liked it. It also kept making me think of Jiminy Cricket, for some reason, and Dorian Gray's portrait a few times. I like the sort of ambiguous ending. Is "William Wilson" going mad? Is there someone out there, his twin perhaps, dogging his every move and thwarting him at all turns? It is his conscience? (I'm inclined to believe the last.)
