I use my F5 with the data back. Actually the MF-28, not the MF-27.
Pros:
- you can print several things between the frames (exposure data or date/time, different formats)
Cons:
- Menus are weird
- I miss "dd/mm/yy, hh:mm, speed/aperture". That would be what I would love between the frames, but not possible. Either date/time or exposure info.