Generally the screen is fairly bright, even on the lowest settings. However, I just went to iBooks and noticed that when the iPad brightness is at its min., within iBooks the same brightness level is ~20% and at 0% it is really dim. But when leaving iBooks, the brightness jumps back to its previous level.
Is there are reason for this discrepancy in brightness? Surely Apple isn't trying to make people use iBooks by limiting the brightness of all other apps at a level, which is too high for reading in the darkness.