I'm going to add just a few points.
First, I have seen the Sawstop, and it is a well-made saw, not cheap in any sense. I have not seen a demo of the stop mechanism in person, but I have every confidence that it works as designed. It does have a feature that lets you turn off the stop mechanism, because otherwise it would trigger when sawing wet wood. I believe Paul has correctly described it and how it works. I believe it also uses the blade momentum to help drop the blade below the table when the cartridge is fired.
Second, they have already come out with a cheaper, contractor-type saw version. I haven't seen this, but again, I presume it works fine. I think it still costs about $1500 or more, though.
Third, riving knives are mandated on all new saws sold in the US after a certain date (maybe 2012 or 2014). Nearly all, if not all, new cabinet saws have them now, but all had to be redesigned to take them (the new type Delta Unisaw, which replaced a 70 year old design, and the Powermatic 2000 that replace the PM 66 are the two most prominent). I don't think most dinky jobsite saws have riving knives yet, but they will get them.
Fourth, the Sawstop inventor p*ssed off a lot of people here, not just other manufacturers, by trying to get his mechanism mandated by the government. As a consequence, the Sawstop has become a religious issue on US woodworking forums and some have even listed specific rules on how to discuss the Sawstop and keeping things civil, or the threads get locked down or even erased right away.
Fifth, the Ryobi lawsuit outraged a lot of people. However, there are stupid people everywhere, and the Sawstop technology might have been the only way to keep this silly person from hurting himself. Euro-rule guards would not have helped. By the way, you can bet that suit is on appeal and may not stand up or serve as a precedent.
Sixth: Given that, however, people with expensive saws are much less likely to do stupid stuff than somebody who bought the $99.99 special at the big box store. There will always be saws too cheap to have Sawstop type mechanisms. So the cheap idiots will continue to hurt themselves. They have not invested the time to learn good practices, and poor usage will trump good design sooner or later.
Finally, one type of customer that Sawstops are selling a lot of saws to are schools. This is probably good--there's nothing like a know-it-all 15-year-old to do stupid stuff no matter how many times you tell him not to.
Oh, one other thing: One of the reasons I read this forum is because I find almost everyone here to be civil and good-natured, unlike on some US sites. Unfortunately, Sawstop discussions (along with various Festool rants) have contributed to the sour tone in those places.
Kirk
