I'm probably not the first to ask but which one should we use now ? As I understand it, it started with a very small System.IdentityModel for WCF. Then came the Microsoft.IdentityModel classes which added a whole lot more. This is the situation as in http://social.technet.microsoft.com/wiki/contents/articles/1898.aspx#v3q10
But now in 4.5, I see that System.IdentityModel has almost all classes from Microsoft.IdentityModel (although there seems to have been some refactoring and the configuration in web.config is slightly different).
Now Microsoft pre-releases a JSON Web Token Handler as a nuget, which depends on Microsoft.IdentityModel AND System.IdentityModel. (JWTSecurityTokenHandler resides in Microsoft.IdentityModel.Tokens.JWT, derives from System.IdentityModel.Tokens.SecurityTokenHandler).
This is getting quite confusing. Does anybody know which one I should use ?