After reviewing all the different methods of executing criminals, I find the guillotine the least “cruel” of all. Put head in place, pull cord … swish … dead.
As long as the blade is sharp there is little, if any, chance of a mistake.
Drug the criminal if necessary to satisfy the “death without pain” bunch.
The guillotine is one of the few things that the French can be proud of.
The only drawback to the guillotine is that the head apparently can still remain aware for another 5-7 seconds after decapitation, which can't be fun.
Still, if you're executing somebody justly, you're not trying to make it a fun experience. Perhaps as with little pain as possible, but there's nothing fun about being executed even if it's entirely painless.
A lot to be said in favor of the guillotine, particularly for use with the jihadi who I've heard have the superstition that they cannot go to the islamonazi paradise for their 72 virgins if they don't have their heads.
In addition, the guillotine can be used for efficiently chopping cabbage for the meals in the pen when there are no executions scheduled.
The French really should be proud of the guillotine! You failed to mention the entertainment value it afords. The drama and the terror of it all! Sure and swift. It would make great television fare if we ever got to that point. The best part is, that with all that, it probably is pretty much painless.