[efattah]

Suppose you black out and the vest brings you up, and you're either alone or your buddy is out of range or away. What are the chances that you will actually wake up on the surface? I have witnessed many bad blackouts in competitions where artificial respiration was required in order to revive the diver. In particular, air flowing over the nose is an important factor to waking up. With the vest, you are still wearing your mask upon surfacing. I would think there is a serious chance that you will simply never wake up, and you would just die from brain damage anyway.

If your buddy is around of course he could come and revive you (take off your mask, breathe on your nose or do artificial respiration). But if you don't have a buddy you may be out of luck in the case of a bad blackout (probably okay for a minor blackout).