MS Word’s native bibliography/citation handling?

Both MS Word 2007 (Windows) and MS Word 2008 (Mac) claim to have citation and bibliographic features for writers who need that support - though with a limited set of bibliographic styles. Does anyone have any experience working with them or compared them to a third-party add-on like Endnote? If you only used the supplied styles could you do away with EndNote (and the perennial compatibility problems whenever the OS, word processor or EndNote gets updated)?

Links:

• Create a bibliography - Word - Microsoft Office Online (Word 2007).

• Microsoft Word Processing Software for Your Mac | Mactopia (Word:Mac 2008)
• AppleInsider | Road to Mac Office 2008: Word ‘08 vs Pages 3.0 [Page 3] (Some screenshots of the tools)