I am confused as to which ArcGIS SDK I should use for developing a ArcGIS map-based Silverlight application.
I just signed up and downloaded the SDK isntaller from ESRI: http://help.arcgis.com/en/webapi/silverlight/index.html
But then i noticed that Codeplex has their own SDK: http://esrisilverlight.codeplex.com/
Which SDK should I be using? Or are both the same (i doubt this)?
* UPDATED *
Or should I just go with the Silverlight Bing Maps API???