This is a strange and gorgeous piece. I love classical music and I normally shy away from the modern "strange" stuff, but there's something about this piece that is just beautiful. Soaring vocal lines over a dense minimalist texture. Words like "ravishing" come to mind for certain parts (for instance tracks 5 and 6).
The vocal parts don't "act out" any particular character, rather they seem to be intoning Shakespeare's words, almost as a sort of incantation.
I tried to find a DVD of the loosely associated movie Prospero's Books, but good luck with that! It's weirdly hard to find.