I have heard great things about the Aftershokz, one of my clients recommended them to me. Unfortunately, music is out of the question here, though I love music in my car, and it would be great to ride with music-- no judgment for those who choose to take the chance.
I just want to identify one problem because it's a very specific auditory and cognitive trap: Blind curves and electric cars = little or no audio warning.
It doesn't happen often, which almost makes it more dangerous because when you haven't had a close call in a few months, you start to unconsciously assume, "Ah, I've finally got this, my riding skill improves every day, and I have eliminated all possibility of collision." And you get careless.
But there it was just last night, rounded a curve at 20-23 MPH and there was some kind of electric land yacht barreling straight towards me at the same speed. Everyone did what they were supposed to do; I did lock up the rear wheel for maybe a second, but it slid to the outside, pointing my front wheel exactly where I needed to go. I released the brakes for another second, got way over to the right side of the road, applied the brakes again, and both vehicles stopped with 10-15 feet of clearance-- a bit closer than I would have liked, but acceptable.
I do not know whether I heard the car or saw it first, but if I'd been blasting punk rock when that happened, no matter what kind of headphones, that would have to eat up at least half a second of reaction time. For non-electric cars, during the day, it's usually my ears that warn me.
The weird thing: At twilight, with a good headlight, canyon riding is actually safer. That might actually be okay with music, because no one will forget to drive without headlights here, it's barely even possible.