We've had the bell debates on here. I was always in the camp of 'a voice is more friendly'. I have to say, now I've found a bell that doesn't ding at every (any!) pothole or rough surface, I'm totally converted, and couldn't hold a view any more different than that previously held.
The bell I have has a very clear and very loud ding. So has been heard from a good distance away, meaning I'm not scaring anyone out of their skins, and for that personal touch I then simply thank people when I go by.
It's brilliant. Forget every anti-bell post I've ever made!