Xfire works for me on a new game(well within a day or two max) in most titles. There has been a single period this year in which drivers weren't coming out monthly, over the past 4-5 years there have been frequent drivers and not surprisingly complaints about how AMD suck because they need loads of new drivers rather than ones that just work. Then when they became spread further apart the bashers changed their tune immediately to complain about the exact opposite.
Still, TW3, maybe the biggest title of the year, Gameworks, in single card which is what 99% of Nvidia and AMD gpu usage for gaming, AMD had that title from day one, Nvidia required multiple drivers to get it stable for their own users despite it being one of their own titles.
Nvidia has problems with single card(and sli too obviously) stability in WAY more games on launch than AMD has issues with xfire and that has been the state of things for donkeys years now.
AMD, small percentage of users, like extremely small have trouble with xfire but can still play the game fine on single card. Extremely large percentage comparatively of Nvidia single and sli users experience problems far more frequently and as often on Nvidia sponsored games.... but AMD has the driver issue. Laughable really.