Honestly it's a crap shoot, but AMD cards are so much easier to MOD, since the BIOS are locked for all GTX 10 series cards.  If you have the time and wisdom to play with nVidia GPUs, I tend to get better results on my 1060 6GB than on either my RX 580 4GB or 8GB cards.  They all ride about the same, but since I have more control over the machine with the 1080 & RX 580's, it produces about 10-15% more hashes average.

I am not even trying to distinguish between brands, much less models here.  Just speaking in generalizations.  If we all could get Titan V cards for the price we USED to pay for RX 480's, we would be golden!