A good chunk of the engine runs as a service now tool, which is good news for people forced to run it on Terminal Servers. Previous versions used to spawn 3 processes per user per login. That type of overhead adds up really quick. I'm also happy that Microsoft Spy, who works on the Windows Defender team, is back on Something Awful forums, giving updates and help as much as he can.
Download URL:
http://www.microsoft.com/downloads/details.aspx?FamilyID=435bfce7-da2b-4a6a-afa4-f7f14e605a0d&displaylang=en
aka
http://tinyurl.com/c9p2f