Yes, its more expensive, and it adds autofocus, I think I will buy this lens at some point soon, but the MF version works very well and frankly you can get the Mamiya versions as demo / old stock damn cheap as long as its the Mamiya 120mm f/4 Macro MF D its the same lens.
Personally, I only DONT use MFD if I'm doing available light and need more light then its D3s time.