I have the 80mm 2.8 leaf shutter lens for the 645 Pro I just recently acquired. the lens is wonderful and to be honest I have printed negs shot with the 80mm Hasselblad lens I had prior and the 80mm mamiya lens I have now and the 8x10s look almost identical IMO when it comes to image quality.
The leaf shutter I know is for flash work and syncing up to 1/500th. I rarely do flash photography so I wont fully utilize its capacity. But the lens is tack sharp and wonderfully bright and easy to focus even for me and my horrible vision.
hope that helps.
I can post some shots from it if you would like.