Sounds like a great idea! A little pricey for average riders, but the cost will go down as it becomes more popular. We will keep an eye open for it.
I haven't ridden for well over a year because of the terrible accident I had. I would like to ride again but want protection this time. I can see that this vest isn't entirely safe because if you don't separate from the saddle, e.g. you go down with your horse, it won't help enough. But, the concept is great and well worth the money. Paying $700 is better than 7 broken ribs in multiple places with a punctured lung and $70,000 in hospital/medical bills!