Networks

I read that Windows Server 2008 uses a new printing format called "XPS" for formatting. And at times there can be situations where a printer uses the new print drivers for the XPS format, but the print device itself does not support XPS. So what i am trying to figure out is how Windows Server 2008 can somehow manage to deal with legacy print devices with XPS. And if their are any benefits from using XPS over GDI-based printing. Some people think GDI is better than XPS and some others did not! What do you guys or gals think???