We are setting up our Project Tracking Tool in SharePoint that we want to do some reporting off of in conjunction with some other system data (Time Tracking – .Net application outside of SharePoint) so we wanted to use External Lists so that we could easily create reports with both tool's (Project Tracking and Time Tracking) data. However, our form for Project Tracking has some component behavior as well some hidden fields we'd like to leverage with the qListForm…so we wanted an external list as well as the ability to control the form behavior.
Let me know if you have any further questions.