The RX 460 is still a very new card and a jump to the 470 won't provide much better performance and is kindof a waste of money. I would say it is only justifiable if you are upgrading to a: RX 480, GTX 1060, or GTX 1070 and up.
It depends on your build but the GTX 1060 is priced the same and performs better than the RX 480. If you like Radeon cards, go for the RX 480. You WILL see a difference.
The RX 460 is still a very new card and a jump to the 470 won't provide much better performance and is kindof a waste of money. I would say it is only justifiable if you are upgrading to a: RX 480, GTX 1060, or GTX 1070 and up.