I agree with all the above and I do carry and wear the kit. BUT the most useful thing you can carry is fuel. The traditional way to die in a small aircraft over the north Atlantic is to arrive somewhere, discover the weather is bad, not have fuel to go anywhere else and kill yourself trying an approach. You may say things about alternates but there are not alternates in many places (though the situation is much better now around Greenland etc).
If you need to worry about ditching a fixed undercarriage aircraft you have probably cocked it up already. I would expend more effort trying to avoid ditching in the first place.
eg better comms, real time weather, engine maintenance, better knowledge and MORE FUEL