The first one. Highly saturated colors are fine in small amounts, then it becomes irl pain. They don't even look good in the finished drawing! ç_ç And for the shaded ref, they can't complain if you got their colors wrong since they should have given you a decent ref/color palette (it's not that hard and I don't understand why they do that). I probably won't accept shaded reference without a clear color palette as a rule.
The second one. It's considered even more painful than the first because that awkward moment the commissioner tells you the colors of whatever he/she/it told you to draw are off because they did not give you a proper reference.
while i hate working with saturated colors but i must say i would rather have the color palette than a decently shaded ref sheet. sure i could spend hours trying to remake the original color that the character owner had intended for their character but that's time i could spending drawing in the lines, coloring and shading. i haven't done commissions or anything but i have tried to redraw some of my characters and had no access to the color palette or previous save file and my god was it a time consuming pain in the ass trying to remake those colors.
though i would still work with whatever you gave (to a certain extent) it would probably just take more time.
i don't do commissions though i wouldn't mind doing them after my uni course