I don't want to risk sounding like an nvidia fanboy here (I used an AMD 7770 to build a hackintosh for my mom)
http://www.kitguru.net/components/graphic-cards/matthew-wilson/amd-radeon-polaris-gpu-benchmarks-appear-online/
But if AMD's mid range card in crossfire can't beat the 1080 I think AMD is gonna be in trouble financially. I'm of the opinion that SLI and Crossfire are being phased out, I have an SLI setup right now and if I could go back to when I built my computer I would have saved up a little more and just gone with one 780ti.... fewer and fewer titles are getting proper SLI and Crossfire profiles, and when I have to force alternate frame rendering it just uses my cards at half capacity instead of using one at full and I still get lens glaring and flicker, I'll maybe get a 5% boost in framerate and that's it. Titanfall, one of my favorite games, is a good example of this. Hell I own Doom 4 and haven't even played it yet because I'm waiting to get a 1080 so I can play it the way it's meant to be played
I'm just so hoping that either EVGA, MSI, or Gigabyte come out with a liquid cooled or hybrid version of the card by the end of June.
I also wish that the 1080/1070's lithography was 14nm FinFet as opposed to 16nm FinFet, I feel that that could have boosted performance even more for the 1080/1070