When comparing the perf/W and perf numbers, keep in mind the feature disparity between each vendors current generation.
Nvidia choose to limit the double rate half-precision (as well as the efficient pack/unpack instructions) to the GP100 only. AMD did include this in Polaris.
This is a pretty low hanging fruit for developers to pick (definitely easier than fiddling with a custom packed structure), so it's unlikely that upcoming titles will show the same relative efficiency on Polaris as current ones do.
Plus, Nvidia is most likely picking the best case, not an average over multiple titles, when comparing the 1060 to the RX 480. Where as the power management of the RX 480 is currently simply broken in a couple of titles.
Unless Nvidia can back their claims regarding efficiency against the RX 480 running the driver hotfix being released in the next few days, and list in detail in what setup they compared the cards, I wouldn't give anything on their relative numbers.
Last but not least: Giving the "exceptional" availability of the 1080 and 1070 cards, does really anyone expect that the stocks for the 1060 currently look any better than that?
Or is this just going to be yet another paper launch, with barely enough cards available to stir up some PR, but not to actually supply the demands?
Heck, even if Nvidia intended a MSRP of $300 for the 6GB model, if they don't get the stocks ramped up better this time, we are not going to see these cards for less than $350-400 in retail.