Screen type? refresh rate? FoV? Resolution?
None of that is known yet. All MS announced was the starting price point, the list of partners (HP, Dell, Lenovo, Asus, and Acer), and that all of these will have internal tracking systems.
Edit: Acer was working on a 210 degree FOV VR headset, but I don't know if that is the same headset Acer is working on with Microsoft. I don't think it is.