kiniku :
None of this will touch Pascal. In the meantime Nvidia is now working on their Ti derivative which will probably be an HBM2 product.
Polaris 10 and 11 were meant for mainstream market. Meaning $100>200 range. I suspect Polaris would even go at entry level, the sub $100 range. I also expect Polaris eventually gets embedded to AMD's APU, along with Zen.
Your comparison will be a very good question once nVidia release the GTX1060 as Pascal's mainstream card. For the top end for this generation AMD has planned Vega, which will came with HBM2 that supposedly will challenge high-end Pascal. Yes, including the 1080Ti. Perhaps the Pascal's Titan as well. At this point, who knows.
Expect Vega based chip somewhere above $300 price range. And as usual from both sides, high end segment by each generation almost always came with the latest near-experimental innovation that will also carried out or gets better on the next gen beyond. Well, some stuff that were deemed good-enough gets re-branded now and then, but still. And now, D5X vs HBM2 is an interesting proposition for high end cards. Who knows what's next.
Since people that actually buy those ultra high end GPU are so few, it's more like bragging rights. Not many people, at this speed of innovation for PC tech, could justify any more than $200 for a GPU. At least not for a tech savvy ones. Including myself.
imho, AMD has made a wise move to gain attention on this segment first. Still, I can't pull the trigger unless I'm aware on how the GTX1060 would fare.