I don't see the power intake being much of a factor. 120 watts vs 150? 30 extra watts is going to save you a bunch of money? I have seen some videos where RX480s did not consume over 100 Watts.
SEE HERE:
https://www.youtube.com/watch?v=zWASNajSdpg&t=497s
The power difference is so minor I don't think it should be a decision point.
At one time the GTX 1060 was thee choice however the recent improvements and Relive driver updates has made the RX480 a viable option.
I personally think both cards are relatively even at this point so its a very tough call.
I think what you need to do is write down all of your favorite games and see how many of them are optimized for Nvidia vs AMD then add them up and go with that choice.
It may simply come down to price.
If you plan to buy a new monitor I think would go with AMD to take advantage of Free Sync.
Not sure if this helps. Let us know what you pick.