Well... I don't own one of them BUT read a lot and...
Vapor-X voltages locked are no fun, Twin Frozr problems with mem cooling, DD from what one of people here said problems with VRM cooling, Gigabyte has coil whine...
From what I've read and had in my life I would say: go either for HIS IceQ x2 or IceQ turbo cooler (great overclockers), or Asus DC II (for great and silent cooling solution).
My budget doesn't allow me to take anything better than Gigabyte (it is the cheapest in my country) and that's why I'm getting 7870XT.
But I think best of the best is IceQx2. Besides - had 3 HIS Radeon cards already, RMA'd only once - no problems with service at all. HIS cooperated with ATI for ages. It seems they know what they're doing.