Soldato
A 1080 is a good doubling of power compared to a 970.
And perfect for a 1440p resolution. 60hz is a limiting factor tho. I think actually the 1080 is too much power for that refresh rate.
My suggestion is if you have a Gsync panel then do some homework on whether a 1070 is better than a 1080 for you. If you have a Freesync panel then same applies Vega 56/64.
I have neither a G-Sync or Freesync panel - couldn't justify the cost and not fussed by 144Hz/FPS. 60 is fine for me. I'll look more closely at the 1080's then and see if I can cram one into my case!