I am using this combination. Everything is great, though I sometimes receive error messages shooting tethered to FC. But in the field everything is ok, both units work as a single camera, so I think the errors should be software-related. The only thing that sometimes annoys me a little is the power consumption of mamiya: batteries drain in 1-2 trips or sessions. This is normal, I think, but I just can't get used to it after my battery-independent experience with film MF.
BTW, I haven't heard about any compatibility issues in case of AFD...