I don't own ZBrush, but I made some test with Zbrushcentral's sword and head models. These are low poly models with GUV displacement maps. The displacement works extremely well on the sword, but I had to subdivide the head in Cinema4D to get good results. Still, the head didn't look as good as in other renderers, maybe because of the subdivision messing with UV's.
I haven't tried importing a hi poly model, though, as I said, I don't have Zbrush.