With the individual benchmarks behind us, let's consider average performance across those tests. The following chart is based on our DirectX-based results, and does not take Mantle into account.
Its no surprise that the Dual-X cooler allows the R9 280 to stay at its slightly-overclocked state longer than a reference Radeon HD 7950 Boost. On average, that gives Sapphire's card more of a lead against the GeForce GTX 760 in the benchmarks we ran. Other games might show Nvidia's card in a more favorable light, but we do think that these cards are generally on par. Sapphire's Dual-X R9 280 tends to take a slight lead in most titles. In the real world, however, that'd be difficult to notice.
The decision between AMD's Radeon R9 280 and Nvidia's GeForce GTX 760 comes down to features and price, as it has since these two cards were introduced. Folks will favor the Radeon when Mantle, Raptr, or cryptocurrency mining are factors, and the GeForce if CUDA, PhysX, 3D Vision, or GeForce Experience (and its related features) come into play. But it's such a close race that I don't think an enthusiast can go wrong in the this range for either a Radeon R9 280X or GeForce GTX 760 with a nice aftermarket cooler.
Having said that, a quick check on Newegg shows that Sapphire's Dual-X R9 280 is currently on sale for £190, making it hard to find fault with this graphics card from a value standpoint. It was more than capable of running every game we threw at it, even using demanding detail settings and high resolutions, with averageframe rates that never dropped below 30.
True, we're on the cusp of the introduction of AMD's Radeon R9 285. But performance should be competitive with the Radeon R9 280, judging from the specifications. Rumors abound that Nvidia might have new products on the horizon too, and they might change our outlook in the near future. Still, none of these potential changes in the market take too much away from the value prospect of Sapphire's Dual-X R9 280 at its current price.

This card will do whatever it takes to keep below 70° Celsius, it will scream like a lunatic if it has to, but it WILL keep cool... unless, you know, clog the fins with axle grease or something...
I was skeptical about buying this card because it was the second "slowest" R9 280X at the time, but its quiet when you don't need it and strong when it has to be.
Both mine and the one presented are the goldielox zone for the performance/watt franchise.