I love my Airzoundz, but use it for different things. My bell is for hello, and polite warnings, the Airzoundz is if I am actually in danger, or someone has done something particularly dangerous or rude. I can ride a little aggressively at times, but I don't think I've EVER used my Airzoundz on pedestrians. I did use it to successfully stop a dog in its tracks when it ran out at me while fully loaded on my most recent bike-camping trip.

I always use the Dimension "Temple Tone Bell" -
http://www.biking.com/buy-bike-acces...dblk-dome.html

I love the exact tone this one is, and the arrangement of the clapper means I can modulate what sounds I want it to make.