Siebel UI is a system that is more accessible to the general user. It is Siebel’s way of revamping the CRM suite to render the screen much easier to view, and it doesn’t require incessant page refreshing, as is the case in Standard Interactivity (SI) mode. There is also High Interactivity (HI) mode, which is an interface that uses the diminishing ActiveX, and it is a system only accessible for people with access to the internal network. SI, on the other hand, is also not the best choice for people who have access on an external and internal basis, because the appearance looks dated. With Open UI, however, you essentially get a better CRM experience.