Nothing, actually. It's the best one there is. That said, it works best when the receiving site uses the ClickPass button: without that, the login still takes

Nothing, actually. It's the best one there is. That said, it works best when the receiving site uses the ClickPass button: without that, the login still takes longer than it ought to. With the button, it's as fast as Facebook Connect, but it has the downside that fewer users are using it, and that it offers no service BESIDE login. Facebook has an edge there, too, in that it offers functionality that users want to actively use, so FConnect is a logical extension rather than a brand-new concept.