Our review of Windows 2008 Server Editions is online at NetworkWorld or in the print edition. The good news, better and certainly more feature packed than before. The bad news is that the Hyper-V technology is not out yet, and some of the benefits are very Microsoft-specific.
Links include: http://www.networkworld.com/reviews/2008/022108-windows-2008-server-test.html and others will be posted shortly.