The R9 380X is AMD's new mid-range offering. According to the reviews it is about 12-19% faster than the GTX 960, but it can't compete with the GTX 970. There's not much more to say. It is just a R9 390 with slower clocks, fewer unified shaders, fewer texture mapping units, fewer render output units, half the RAM and half the memory bandwidth.
I'll add the card and some of its retail boards today.