I did a sod of a hawthorn hedge today - I've just got the last thorn out - it was a particularly difficult one and needed some extra access via a Swann Morton scalpel.
But, I did wait until you'd finished your tea.
I have the British version and the coupling has required considerable fettling - it's still not 100% reliable, though it is a lot better than it was straight out of the box..
Polystyrene / styrofoam cutters have been around commercially for a long time - many different formats are available.
Much used in R/C aeromodelling, etc.