I used to think my Aerostich had enough armor for anything but after breaking a good chunk of my right shoulder last fall I looked harder at these airbag devices (funny how an injury focuses the attention!).
Picked up a YS vest the other day in the mail from Safermoto and tried out a test inflation at work on Friday:
-vest is well made, looks like a quality piece. Bulkier, and I'd guess warmer, than the Icon Hi-Viz I had before, but still fairly trim before inflation.
-the inflator is bigger than I thought, feels like an overstuffed pocket. However there is armor behind it, plus the air bag, so it appears it won't cause problems. You can get extra chest armor yet, but I don't think I'll bother for now.
-it takes a pretty sharp tug to pop the trigger, looks like accidental inflation won't be a problem.
-inflation is almost instant, even though I have the old style slower assembly.
-the vest doesn't inflate a huge amount (no 'Michelin man'), but still probably 4 to 5X more thickness than the Aerostich armor I had. Grips tightly, feels reassuring. Starts to release air right away but still holds pressure a considerable time, more than enough to stop rolling, IMO.
-neck is supported very well, and between the 'collar' and the shoulder inflator I think it would have prevented a lot, if not all, the shoulder and head damage I suffered.
-repacking was surprisingly easy, a few snaps.