Every time I've tried it it's been an absolutely hellish experience. It abstracts too much of what the scanner driver is doing. I don't know what units it's doing things in. It snaps input numbers to the nearest number the scanner driver supports (if I enter "5" it'll change to "4.998" after a second), but again, I have no idea what it's actually measuring because everything's in scaled floats when it shouldn't be.

Auto exposure uh... happens, but I don't get to know what it's decided, nor can I set it manually. I can "lock" the auto exposure for all frames in a strip, or I can add or subtract from the auto-chosen value. Do I get to choose the value though? Nope.

If it runs out of ram it just deletes previews and makes you scan them again when you go scroll back to them (you can increase the ram limit in settings to mitigate this), losing your settings for that image.

All in all, I'm glad I can use my scanner at all, but it's too buggy and I wish they would let me pay for their huge amount of reverse engineering effort as a driver and write my own TWAIN software on top. From what I understand it's just a two-man team behind it and I think it's just too much to expect them to maintain the amount of complexity they've signed on for, so I can't be mad. However, it does sound a lot like that FSF/GPL origin story where RMS got mad he couldn't fix something in the printer software.