Silverlight 3 has the ability to provide variable streams up to 1080p based upon the user's connection speed and CPU power.
Silverlight 3 also offers an improved audiovisual experience overall, with better 3D rendering and animation, higher resolution video, and MPEG 4-based H.264/AAC audio.
Another bonus is the "Out-of-Browser" feature that allows you to run outside of the browser window without any additional plug-ins, and without necessarily needing an Internet connection.
