The Xbox One runs the game at 1080p 60 fps and the Xbox One X runs the game at 4K 60 fps.
We got the chance to check out a preview version of the Xbox One X game (not the Gamescom demo as Dave mentions here) and stack it up against the base Xbox One and PC demos. The preview build has some differences (principally a colour shift - but to be clear, this is not incorrect HDR footage), but there's more than enough to show us how PC stacks up against both consoles.
From Dave's findings, the Xbox One X appears to offer the "high-end PC experience" allegedly offering identical levels of quality, with the main difference Dave spotted being the implementation of AA, as MSAA can be increased up-to 8x on the PC, whilst the Xbox One X appears to be using AMD's EQAA.
Compared to the base Xbox One, the Xbox One X offers longer draw distances, environments with a higher level of detail, increased foliage density, higher resolution textures and better anisotropic filtering. In the demo the anisotropic filtering on the Xbox One appears to be around 4-8x.
Digital Foundry plan to take a more in-depth look at the game when it launches.