I am of the “if your number’s up, it’s up”, camp. I can’t find it now, but I saw a recent post of a guy talking about the gear he wore, and why. He had relatives with 2 differing helmet experiences....
The first, his father (or possibly father-in-law), was nudged out of his lane, separated from his bike, and flew across the median strip. He was wearing a half helmet and t-shirt. He suffered very bad road rash, but no facial/head injuries.
Then, he had a cousin wearing a full face, who was involved in an accident with a truck. A star picket came loose from the truck and went straight through his full face, killing him instantly.
Every crash is different. Do your research, determine the level of risk you are prepared to take, and wear what you are most comfortable wearing. I wear a Shoei J-Cruise 3/4 as the helmet wraps around the jaw more than many 3/4 helmets, and despite earlier comments to the contrary, it does indeed give better peripheral vision that my Shoei Neotec, which I no longer wear.
Pete