Librarians were packed in like sardines at PLA (apparently; I wasn't there) to hear how Rangeview Library District, Colorado and the Maricopa County Library District, Arizona, tossed out Dewey in favour of "systems based on the BISAC (Book Industry Standards and Communication) subject headings."
I'm still very skeptical about this, but I do appreciate putting all poets together, regardless of nationality, come to think of it.
Dewey can also be a mess for some areas: biographies, anyone? True crime? This is reflected in the collections that have seen better circ since the changes at Rangeview: "circulation of biographies has doubled in most locations. Teen nonfiction has tripled. Also booming is test preparation. “People weren't finding that stuff in Dewey,” Rangeview's collection development manager said.