I have one.
Very nice lens.
However keep in mind that you cannot use the full tilt shift of the Fuji gx680.
The image circle of the 50mm is a bit smaller than the other lenses
If you are using a nonstitch MFDB setup it won't effect you due to the 50% crop
here is the info:
Also PM me your email and I can send you my pdf file collection with loads of info on the GX680