Tease my tra la la
Mmmmm my ding ding dong
Those rock materials in the back will likely look awful when compiled, i'm pretty sure the bump/ normal/ whatever they use for artificial depth don't wrap vertically (not to mention the basemap's obvious seam). You'll probably want to increase the material's scale for those cliffs.
The displacements themselves are pretty nice, though i'd recommend playing with a smaller brush size to give them a little more definition and reduce the clay-like soft forms.