xrongor responds:

im not going to defend saw stop. but im not going to take it on the word of
JClarke that it doesnt work either. the theory is sound, and they are
either totally faking those demonstrations, or i think its clear that less
people would be hurt with them even if it didnt work 100% of the time.

I've seen it work---with a hot dog--at least on video. I don't doubt the theory
works, but is the application practical. It prevents, primarily, amputation
style injuries. How many of those are there a year? Is it worth having every
table saw in the U.S. built, or retrofitted, with a device that currently costs
about $500 to save 50-60 people from their own misbehavior? If the figure is
even that high.

That's what is more likely to cause this to become vaporware than any doubt
that it actually works. Economics. A proper crown guard with a splitter will do
about 95-90% (my guesstimate) of what the saw stop will do. Total cost is
probably about $50, and allows the makers to dump the current crappy
splitter/guard assemblies, to reduce costs even more.

Charlie Self
"It is even harder for the average ape to believe that he has descended from
man."
H. L. Mencken