I used to do that a lot, stay up the night before and study. Actually, I did it all the time ahead of exams and it works really well, I'd have the facts in mind really fresh. And because I was reading it for the first time it wasn't as boring either. You can make up bigtime for not doing much throughout the semester that way.
The the thing that really pisses me off with exams (or should I start calling them finals) is considering how much is riding on it, you'd think the teacher would put some effort into making a sensible exam. The full 5 months of material goes into that, and quite often the exam sucks ass, doesn't give you a decent chance to demonstrate your skills. I once had this terrible teacher who gave a truly sucky exam, contradicting herself vis a vis what she had said just the week before would be on the exam, and then proceeded to grade 70 or so papers in 2 days, unheard of. The grades seemed more or less random, more than half the people violently protested and they had to do a special re-exam to fix it.