I can't say I have every seriously thought about wearing a vest. I packed one, once - when I first started out. Never did make it on. I'm not exactly hard to see, and if someone doesn't see me as I am they sure won't see me with a vest on - they are 100% not paying attention. Nothing you can do about that.
In lieu of a safety vest, I am confident that my bright lights will be plenty of indication that I am there.