>Hi Craig
>
>I understand about the data flowing back, but does it not also take time to trigger a function in the DLL, passing parameters etc. Isn't end-to-end testing required to see what pieces to disregard?

Yes, you will need to do end-to-end testing, but if you need a distributed system, COM (COM+) should be faster than web services. If you're just hosting the application on the desktop, there is probably no reason to use COM.