Reviews for the RTX series are still hard to come by but little bits of info are showing up. According to a square enix test the 1080 Ti is about 28-31% faster than the GTX 1080 Ti. Problem is its a 71% price increase for 30% performance bump.
The last generation, 980 to 1080 was a 50% performance bump with only a 9% price increase.
So its still not looking positive for the RTX series.