As an owner of the D850 and the H6D-100c I find the DxO results to offer an excellent correlation with what I see in real world photographs.
The X1D is an excellent camera and the color profile and very good, but so is the D850.
There are other advantages, such as great lenses, an EVF for those who like that, leaf shutter lenses but the magical sensor properties of these small MF sensors are IMHO mostly a myth. They are a bit better than FF, that’s it.
The larger MF sensors have of course a much more significant advantage.
Cheers,
Bernard