As the days are getting shorter I've been riding with a front flasher and immediately noticed a difference in drivers behavior toward me. I'll be staying with it.
I generally ride a rear flasher, it's free, it can't hurt and has a real effect in low sun conditions (ie commute hours).

Hy-Viz is certainly noticeable to most people, except the 8% of men who are color blind.
I have a color blind friend who can't tell screaming hy-viz lime green from beige. But he can see a white flashing headlight like anyone else.