Not how it works a gtx 1060 cost the same and this beats it.
590 vs. 1060
590 wins in performance only(10% higher vs. stock reference 1060)
1060 wins in overclocking headroom(both overclocked the difference is much less than 10%)
1060 wins in price/performance(slight)
1060 wins in performance/watt(massive)
1060 wins in power consumption(half the wattage for 90% of the frames at stock)
1060 wins in form factors(590s are ginormous, while 1060 can fit in small cases with ease).
1060 wins in most areas while being 2.5 years old...
580 vs. 590
590 wins in stock performance only(10% higher than stock reference 580)
580 wins in overclocking headroom(which can put it on par with 590 at $80-$100 cheaper for 8 GB cards)
580 wins in price/performance(major difference)
580 wins in performance/watt(very slight)
580 wins in power consumption(slight)
AMD has failed to beat 1060 with the 590. The old AMD cards are great value right now though as they are much better value compared to the 590 and 1060(as long as you don't care about power draw and don't have strict GPU size requirements).