The IsSameAs method returns True if the Recipient object is the same as the Recipient object being compared against.
objRecipient.IsSameAs(objRecip2)
Two Recipient objects are considered to be the same if and only if they are instantiations of the same physical (persistent) object in the underlying messaging system. Two objects with the same value are still considered different if they do not instantiate the same physical object, for example if one is a copy of the other. In such a case IsSameAs returns False.
The IsSameAs method ultimately calls one of the MAPI CompareEntryIDs methods to determine if two objects are the same. This is necessary because, although MAPI requires all entry identifiers to be unique, it does not require two of them identifying the same object to be identical. A generic comparison of any two objects' unique identifiers is also available with the Session object's CompareIDs method.