Above and below are the photos of the Radeon R9 280X, R9 270X, R7 250 and R7 240 adapters.
You'll see that the Radeon R9 278X comes with Dual-X and Vapor-X coolers, and different factory overclocking settings.
That's why, instead of the $299 / €299 price, two of them are close to the $349 / €349 mark.
The Radeon R9 270X is also factory overclocked, and also in three options, with the same coolers as above. They cost $199 / €199 to $239 / €239.
The R7 260X, R7 250, and R7 240 should sell for $89 / €89 to $199 / €199 of their own.