"Awesome"... a HD5870 with DX11 max details tanks at 1680x1050 already. Not even 30FPS average... If other games follow the same pattern, DX11 will be a useless feature on those cards (the whole HD5xxx series) as they won't be able to push games at good resolutions with smooth framerates... Now, add Eyefinity and this is just laughable.
So the Radeons have DX11 (can't use it fully, cards too slow), Eyefinity (cards too slow too), OpenCL (nothing here yet so no idea, I wouldn't hold my breath though) and are pricey. The only reason to buy one now is for current games only - at least those play very good. Anyone giving those features as arguments for buying the cards "for the future" might as well write "blablabla".
Did I forget something? Ahh yes, the HD5830 has DX11 and Eyefinity and that's why it costs more... LOL