I would get Vapor-X.Sapphire's HD 7950 Vapor-X comes with a large dual-fan cooler that uses the company's famous vapor-chamber technology. On the Vapor-X you will also find a "Lethal Boost" button which switches to a second BIOS with higher clock speeds. With this BIOS, clocks are increased to 950 MHz GPU and 1250 MHz memory.
I was facing the exact same conundrum, and was checking these links weekly: http://pricespy.co.nz/product.php?p=1105772 http://pricespy.co.nz/product.php?p=1379702
At the same price the Sapphire is slightly better value, since it is clocked at 950MHz vs Gigabyte's 925MHz. Both will safely overclock to over 1000MHz tho, so it not really a major issue. I'd go for whichever is cheapest, but the cooler is slightly better on the Sapphire card. Both have solid caps.
Haven't been any price drops in either for many weeks. Then Playtech did a one day only 15% off everything deal two weeks ago and the Sapphire board was suddenly $424 shipped. No brainer.