Agreed--and the guillotine blade is reusable. Very ecologically correct. Plus, there's no risk of the condemned getting lead poisoning from the bullet...
--yep--nobody ever had to be guilliotined twice--
Because nobility could chose a fine blade, while peasants were beheaded with a less efficient axe (sometimes requiring two to three chops if one were clumsy or did not possess the required strength), this method was deemed inhumane and unfair. The guillotine was efficient for everyone.
The advance of STD and blood-related diseases would make clean up after a beheading a messy business, indeed. The upside though is that it is economical (requiring no electricity, and other expensive precautions - only sharpening after every execution to ensure a clean cut the first time down). Furthermore, the prisoner need not even be conscious throughout (which would prevent the shocked look of horror on the face, as the brain retains at least enough blood for conscious thought for up to a minute afterwards before dying from blood loss).
(If I've freaked you out, don't fret! I studied this topic for a book of mine, so I know more than the average person does on it).