I don't often read longfic (yes, I consider 40k to be longfic) in one sitting, but this I devoured in an afternoon. I don't often read Buffy fic these days either, but I clicked on Sock Puppet out of curiosity, and I just kind of never unclicked, if that makes any sense.
It's a compelling read, and very very well written. There's also a very interesting DVD commentary that you can find here.
bloodwrites