Take a look at my signature. I have a 1080 for Windows gaming but I'm about to return my 1070 and swap it for an RX 580 for macOS as soon as they're in stock on Amazon. (Yes, even with the supposed performance hit.)
NVIDIA web drivers are a pain to use and not that reliable in my experience. Definitely worth getting an RX 580 over a 1060 without a shadow of a doubt.
If this were a PC and not a Mac, then yes, sure, get the 1060. But if that were the case you wouldn't be here on MacRumors
Still get an RX 580 even if I am getting the GPU to bootcamp game? From what uninformed reading I've done it seems the cards will be held back by the processor anyway...