I’ve never noticed in myself any impacts from consuming caffeine. I regularly drink caffeinated diet sodas while going to sleep (that is, if I’ve started one I’ll just leave it on the nightstand as my drink on hand should I wake up thirsty in the middle of the night).
I tend not to be a person who has difficulty waking up or staying awake (all of my all-nighters over the years have been unassisted) but when exceptions happen I’ve never found caffeine to be of any help. I’ve never tried any of the really high dose stuff (don’t like coffee and rarely have never even tasted a Red Bull or other energy drink) so maybe it would be different if I tried it at those levels.
However, if I do get into a period of heavy caffeine consumption (once had a job where soda was free and I got into a more than a six pack a day of Diet Coke habit), I will get withdrawal headaches when I stop.