It is rather spooky at first, but once I got over that its excellent for blocking background office noise.
Now what would amuse me NO END would be if once, (and just once) after a few hours, it was coded to fade out and play a distinct voice along the lines of "You're going to die today". I'd love to do that to someone!
At least for me, the fact that I can't pick out any real words/phrases makes what could be believable background/nice sound feel like it could be from a horror movie.