My main problem with scanning prints - the majority of my work is in color - is color balance. I'll scan, and for a number of reasons; integrity, and conforming to the idea of, "The least PS-type tweaking possible" - my images will result in many telling me my prints are "too green". I can assure you, I take great care in color balance with the originals - and the balance looks OK on my screen. Each roll of film (or at least one roll in every "session") will have one frame with an image of a gray card, and I analyze a LOT in printing.
It has been suggested that I equip this machine with a Screen Calibrator" to conform to some "standard of color" ... I won't -- costs too much, I'll be involved in an area that really holds no interest for me (read: d*****l), and it would not do much good unless everyone else out there calibrates their screens the same way.
The hue and cry subsided somewhat with my last submission - because I deliberately tweaked to get the image to appear too magenta here (called `Kentucky Windage').
Black and White..? No matter what I do, those scans are invariably of lower quality than the originals; definition is less, tonal scale is less, contrast never seems to be "right" ... I only hope that those viewing them can mentally compensate for the difference in what they see on the screen as compared to the originals.
Possibly, an additional requirement for critiquing should be the posting of a number of images from the would-be critic. That might give them some idea of the "differences".