It's slated to be released in September this year. They've stripped out Avalon, WinFS, precaching technologies, DX10, etc. all the features that would have made it interesting. All it has is a new UI based on DX9.1, and a couple of new (undocumented) network modules to make life hell for other OS developers. Oh, and shit directly lifted from OSX/Linux.

Overall it'll be shit.