This shoot was my first real go of the GA645, and it is a really nice camera to use. Despite it being compact for a medium format camera, it totally dwarfed the other two. Not only that, it weighed almost three times as much as the feather weight X100.
The camera is relatively easy to load and use. Any familiarity with a roll film camera previously will help the user load the camera, but it's no harder than a Nikon FE2. The only tricky bit is winding the film to the appropriate starting point, and also remembering to click the bottom spool locators into place.
When in use it couldn't be easier. I used aperture priority and off I went. The viewfinder is where all the action happens. The finder frame automatically corrects for parallex and changes substantially from infinity to minimum focus distance (approx 0.7m). There is a read out that gives an approximation of the distance from the subject, which is all adjusted by pushing the shutter half way down, just like on a D-SLR.
Being almost totally automatic, the GA645 is much closer to the X100 than the completely manual Leica in terms of ease of use. It really is not much more than point and shoot.
The film I used was some out of date Kodak Portra 160 NC. This is a low contrast film, designed to be used for weddings and softer portraits. It was probably not appropriate for the subject matter, but a good trial film.
I am looking forward to the results!