A 980TI is a little shy of 1070 performance (but really close).
For 1080p gaming it should max everything, and pair well with 144+Hz monitors for e-sports etc.
Saying that, at $399 it's right at the MSRP of the 1070 FE from Nvidia directly (currently out of stock).
https://www.nvidia.com/en-us/geforce/products/10series/geforce-store/
I wouldn't say it's really "worth" getting at $399, when you could get a little more performance from a newer 1070.
But if you need a GPU upgrade and can't wait for 1070 stock..... then it's a pretty amazing card.