From Techpowerup GTX 1080 review and 980ti Gigabyte XtremeGaming review (March, 2016):
BF3 - 980ti at 1492/2090Mhz - 136FPS
BF3 - 1080 at stock - 137FPS
They perform the same in that benchmark.
That explains the sky high price, they know that 980ti is still very powerful card, so to stop prices falling down on 980ti they inflate prices on 1080 which I can only assume clock to clock is slower than 980Ti. I highly doubt that performance will increase with "mature" drivers. I'll stick to my 980 SLI ... or upgrade to single high clock 980Ti if I can score a bargain.