Ed,
Only my opinion...Given the unknown...If you go over unconscious the manual type really does not do it's job...I would recommend wearing a normal, not co2 activated life vest until you are comfortable with where you are hunting...I know these designs do disappear on you because of size, are comfortable, and innovative...It might be used in the boat as a secondary...Alot of guys wear them but I would not chance it...Being an engineer of design and manufacturing I have some understanding of statistics...Anything mechanical will fail in time..I do not want to find that failure mode...Your life and experiences through this web page are worth more than $99...Buy a standard vest...I viewed the same page and found a standard model for $29.00...Save the money and buy more shells...
Regards,
Kristan