Your links actually provide a box.
However the best HD6850 in my opinion is the ASUS DirectCU variant. Offering direct-contact copper heatpipes (DirectCU?) for more efficient cooling, coupled with ASUS SmartDoctor for overclocking, you can't go wrong.
If, however, you want a Sapphire card, the TOXIC or Vapor-X variant is what you should look for. Sapphires' program called TrixX is great for overclocking and Sapphire's cooling system is also nicely done.