Bagged myself an Asus 1070 Turbo on Saturday from a high St competitor (who normally I wouldn't touch with a barge pole but was in there with the Mrs) - she spotted it in clearance under £300! - I was very surprised at the price (they had 1060's on the shelf next to it for way over £330) to be fair though they only had the one in stock so something of a one off I dropped lucky on.
Delighted with the performance boost over my 780ti but must say I'd have been less impressed had I paid the £400+ these cost not so long back.
Equally very glad I didn't take the used 980ti route, I'm seeing near 8GB VRAM useage in GTA V, BF 1 and Battlefront (both with resolution scale at 135%)
Finally I'm enjoying my favourite games cranked fully up @ 5760x1080, image quality seems noticeably better and everything just seems much smoother.
Happy camper.