I am currently working on a project where I am sending a .Net type via ajax to a client application via ajax. I have no issues with the object being serialized and set to the client.
I run into issues when I take the exactly same object and post it back to the server via a web method with the following error:
/Date(1373950800000)/ is not a valid value for DateTime.
JsonDataContractSerializer (default serializer for ASP.NET MVC) or
NewtonSoft Json Serializer (default serializer for ASP.NET Web API).
For a visual example of this date mangling issue as well as possible solutions, check out JSON Dates are Different in ASP.NET MVC and Web API.