A correctly done hanging snaps the neck instantly and is nearly certainly less painful and drawn out than lethal injection. You are basically totally brain dead within I think under 10 seconds.
Obviously an incorrectly done hanging is horrible as you asphyxiate in an extremely painful physical position.
Technically lethal injection methods vary, but the last thing I remember reading about them was… they do not actually render you unconscious and then inject the stuff that kills you.
They render you /paralyzed/, and then inject the stuff that kills you, which more or less make you feel as if your blood is on fire, and this can take up to 2 minutes before it flatlines your heart… brain probably takes longer to die, all in extreme agony.
True, but then you have that whole weird… few seconds of being able to move your eyes and possibly make facial expressions while your head rolls around thing haha.
And yes, a properly sharpened, weighted and … drop heighted… guillotine will lop off your head every time.
Takes a fair amount of strength and finesse to chop someones head off on a block. IIIRC, there are more than a couple recorded instances of bad executioners having to make a number of swings to totally off somebody’s head. Bleeeegh.