The Fujifilm GFX100S has not arrived yet—very tight supply.
I plan to evaluate the GFX100S extensively, as well as to buy it for ongoing work with Fujifilm medium format. Having it always available and under no time limitations means I can finally cover every last in-and-out of Fujifilm medium format.
The persuasive news on the GFX100S I am seeing from some readers is that while all forms of banding/striping might not be completely gone with aggressive 'post', it looks like the obvious PDAF banding* originally present in its sibling the Fujifilm GFX100 for well over a year does appear to have been fixed.
So I am keen to see whether the GFX100S can be pressed into full service for monochrome captures. That is, monochrome derived from color is way more powerful for tonal mapping than a monochome sensor—you get to decide the tonal mapping in raw conversion instead of crude (at best) filtration at the time of shooting the image.
* Better described as PDAF striping, in which the stripes are lighter than everything else. I might flip the terminology to better reflect the actual manifestation.
Starting out with your own Fujifilm GFX100S, Fujifilm medium format?
In this order, what I would get: for landscape use 50/3.5, 30/3.5, 23/4, 80/1.7, 250/4. They’re all terrific, change-up that order if your shooting style demands it. But you cannot go wrong starting with the Fujifilm GF 50mm f/3.5 as an all-arounder for everything.