I guess I make a little more distinction between them. If you think of the actual guillotine the blade came straight down with the edge angled. That angle causes a slicing cut on the whisker, not any side movement of the blade. The scything has a rotational aspect to it and some movement of the blade directionally. Of the two I like the guillotine the best and probably because it's the safest. I use the scything some, mostly on AGT, but some of my most memorable blood letting came from the scything stroke misapplied.

Regards,

Howard