1. An XML Web Service call is essentially a SOAP message sent over the Http Protocol
2. .NET Remoting is a communication infrastructure that provides access to remote objects over the TCP protocol, Http protocol or some other custom protocol
3. XML Web Services uses SOAP (Simple Object Access Protocol) which is an XML message to communicate over the widely used Http protocol.
4. .NET Remoting provides object services over the Http or TCP protocol. .NET Remoting could be a SOAP message over a Http protocol (similar to XML Web service) or a TCP protocol or a Binary Formatted message over the TCP Protocol or Http Protocol.
5. When objects are remoted over a TCP Protocol using Binary Formatting or Encoding you have the best performance over any .NET Remoting Service or XML Web service.
6. If you intend to send SOAP messages over the Http protocol, do not use .NET Remoting, use XML Web services. The medium is the same in both instances and XML Web services deliver more speed than .NET Remoting service using SOAP Formatting over a Http protocol.
7. Using IIS as a Host or server offers scalability to both Remoted objects and XML Web Services. XML Web Services use IIS (Internet Information Server) as a Host and .NET Remoting can use IIS, Windows Services, Windows Form, Console Application as a Host or Server.
8. You can build your own interprocess communication solution using classes from the System.NET namesapce.
9. Using IIS as a host for XML Web services or .NET Remoting service offers security features like authentication and also state management.
10. Binary Formatting over the TCP protocol requires additional ports other that port 80 (which IIS uses) to be opened on your web server. These additional ports could pose security considerations.
11. Using .NET Remoting offers some flexibility for the activation of objects (they can be activated on the server or client), object life time management using leases and object instantiation management (SingleCall or Singleton modes.)
12. .NET Remoting offers access to a richer object oriented programming model than .XML Web services.
13. XML Web services offers a richer set of options for formatting SOAP messages than SOAP Formatting in a .NET Remoting Context.
14. XML Web services uses SOAP to communicate between two computers and is better suited for exchanging messages with applications not built with .NET while .NET Remoting is optimized for exchanging messages between .NET clients.