I worked with 4x5" and a Schneider Super Angulon f5.6/90mm for many years, and switched to a digital back and the SK 35mm and later 28mm lenses starting in 2010.
I only have anecdotal data here, but my impression is that:
- shifting was much easier, because you had no color shift problems
- increasing light fallof was a problem, since you almost could not correct it.
- decreasing corner sharpness was also a problem, but you mostly would not care, since you had to scan the slide at A3 or larger to notice it. Whereas with digital backs, you will always see the corners at 100%. If you look at the cornes at 50% magnification, or at 100% on a macbook retina screen, you will be surprised how much better it looks, IMO.
best,
geb