I have a XFX 7970 3 GB Ghz Edition and I haven't regretted the purchase as it maxes out every game I have played so far with ease. Temps stay cool around 60C at full load. I sold two 6870's and a 660ti to pay for it and it runs circles around those. Dont do SLI or Crossfire if you dont have to due to micro stuttering. Not to mention some titles dont natively support CF or SLI so you are stuck with 1 cards performance. 1 powerful card will always out perform 2 okay cards, just not on price.
This is micro stuttering for anyone not familiar with it http://www.youtube.com/watch?v=zb3MsENJ-fU