I recently cleaned up my library getting ready for a new year. I currently have about 1100 files in my library, mostly favourite images from other years.
28mm images I have 59, 28mm or less I have 128, 31 mm I have 4, 31 or less 153, 35 or less 163. Of the 1100 images in my library, there are only 10 images that I would have taken with the 31 if I owned it. And that has always been the problem, much as I'd love to own it based on reputation, I take a very low percentage of my image with that focal length. The 1100 images represents the images I'd print given a chance over the last 4 years. Paying $1000 for the psiiblity of using it for 10 keepers is simply a little too outrageous for me to handle.
IN the absolute best scenario, where I leave home the 35 2.4 but bring the 40XS, I could have used the 31 for 33 usages with considerable cropping on at least a third of those images.
It's not like my 29-105 is failing me....
Really for 10 images I might have used it on if I had it with me it's a no brainer not to own it. Maybe for people who would use the lens sub ƒ2,8 it would be worth it. I take very few images like that. I have 12 images taken at less then ƒ2.8, all taken with the FA 50 1.7, but I also have the 35 2.4.
In short, I'd love to own the lens, but based on my possible usage, it's not even an issue.