I agree with not wanting to see what is about to squish me. I do, however, like the idea of being able to cross a lane without slowing down to look over my shoulder. The latter outweighs the decision in my mind.
Placement is strictly a matter of personal preference.
I rode with headphones when I first got on the bike. Music is a strong motivator. I quit. Not for safety, but because I discovered I like the sounds of my surroundings more. A zen kinda thing.