This is not really the greatest Bjork single out there - simply because there isn't anything new on it. The material itself isn't bad. "Cocoon" is already on Vespertine, "Amphibian" is on the Being John Malkovich soundtrack. Track two is the only thing "new", but it is based on a Vespertine song - a one minute music box version of Aurora. ONE MINUTE long, no vocals. I don't really consider it to be anything but an impressionistic interlude separating the two vocal tracks. It's sweet, but hardly memorable because it doesn't develop musically.
The ONLY reason to get this single is if you don't have a copy of "Amphibian", which is fantastically mysterious and gentle, complete with harp, whistelling, and subtle drum programming. Equal in quality to any of her other songs. Any Bjork fan should have "Amphibian" in their collection.