I found this with a quick google search. Granted that I've never really tried Xfire (i've heard it's messes with your PC?), the site I found compares Windows Live Gold vs Xfire (Silver and Gold features are included).
http://casualcoregamerpress.blogspot.com/2007/05/xfire-vs-windows-live.html
The only big 'plus' I see to Windows Live is that it works with Xbox Live in that if you currently have Xbox Live Gold, then you also have access to Windows Live Gold. They're trying to unify online PC games, but it's not interesting to me unless it really proves itself to be worth it and no, forcing Vista games to require Windows Live isn't something I'm too excited about.







