The situation that leads us into using WebORB is that we use C# and SQL server on the server side with Flex on client side. The communication has been through SOAP. The SOAP packages can be really bulky sometimes. Performance was not extremely bad but we are looking for better.
WebORB allows our server and clients to communicate through remote objects. I have been running load testing when we were using SOAP. After we put WebORB in place, I ran load testng again and the performance improvement was huge. Parsing XML does take time. No doubt about it.