One major advantage is that you get to see all your contacts on different systems status on one applocation itself.

So while previously I would need to fire up Skype, Yahoo, google Chat (Internet call) , Gizmo seperately to see which of my friends are online on each respective system, with Fring you can now have one app to check all contact across different protocols and chat / voice chat with them all thru one app.

Of course the downside is you lose Video chat facility in Gizmo in the ITT when using Fring (Skype never had video chat, so no loss there).