A console has pretty weak CPU/GPU compaired to PC. The difference is that the console game is optimized for that hardware. So a console GPU = to a R9-270 will perform better then the same PC game with a R9-270.
With all of that said a R9-280x is a great price/performance card for just over $200. Pair that with an i5 or even an fx-8320 and you will be well above any console. Should be able to play everything on high at 1080p, non AAA games on ultra.