the difference between all the aftermarket 1080ti GPUs in minimal as far as FPS goes.
Out of the box, pretty much all of them will perform the same as each other.
As far as the Strix line goes, technically the best one is the OC version as it comes with higher stock clock speeds, so it effectively performs better out of the box
https://www.asus.com/uk/Graphics-Cards/ROG-STRIX-GTX1080TI-O11G-GAMING/