What is the better energy option?!

I am a university student and have never had more caffeine than a can of soda...thats gotta change. I have tried drinking coffee, red bull, monster and Nos. Nos works the best for me but i think thats just because its such a huge can. My roommate drinks black coffee, no sugar, every morning and was telling how bad energy drinks are.

So i need to know whether drinking a Nos(or some other energy drink) once a week, probably more during exams, is better or drinking black coffee no sugar every morning.

Please advise in terms of which option will work better to keep me up, which ones worse for my health(i know they are both bad just pick a poison), and which is overall cheaper.

Thanks a bunch