I am a firm believer. I went from a black/silver riding jacket to hi-viz and noticed right away that people were giving me more room.
In addition, when I bought a helmet I purchased an ugly yellow one....gets lots of comments. That means they noticed.
Further, when riding back from Tenn. summer before last, I was eating at Burger King and a trucker came up to me and thanked me for wearing such high visibility gear. He said that he might not have seen me if I hadn't been so colorful. That was enough of an endorsement to me.
I am an HD rider and do stick out like a sore thumb. But, two of my hi-viz jackets are HD day-glo orange/black. Man are they obnoxious!!!
I routinely get lots of comments about my gear. But, I have never had anyone treat me weird about wearing it. Sure, I don't look like a badass, but I never was one really anyway. Hard for a Science Teacher to be a bad ass....unless he is breaking bad.
Because it is my bike and I like it that way!