The ones on the mup with no leashes are worse. There is NOTHING more unpredictable than a dog wandering along somewhere behind its owner. I find young children to be less of a hazard. A bell won't help you much with a dog either. Now an airzounds might... or it might just jump right in front of you.

Almost the exact opposite experience for me:- bells seem to be instantly recognized as a friendly cyclist way of letting people know you are near them and a high proportion of them do exactly the right thing. If I'm only slowly gaining on another cyclist I'll use the "friendly hello" as I pass. In that case I sometimes get ignored if it's a female (which is not unreasonable), but 90% say something equally sociable response.

I just call out "good morning!" (or appropriate time of day). Seems friendlier and people seem to turn around and we make eye contact which enables me to pass safely. YMMV.

I just use the bell a couple of feet back with a combination on your left depending on the reaction. Also would like to note that here in NYC from what i heard from Bike New York air horns are technically illegal on a bike.

Bells/horns don't work, their not loud enough to do anything in traffic, you can yell louder, and you can't slow down fast enough if you're operating a bell instead of a brake. If you could mount a horn in such a fashion that you could operate a brake with the hand and the horn with the thumb of the same hand then maybe that might be useful on rare occasions.

Incorrect. My airzound is 115 db. That's louder than the horn on both my truck, and my motorcycle.
I can easily operate the horn while braking, and even downshifting. "Rare occasions" is almost daily use of the horn around here. Everyone's situation is different. What you say may be true for you, but it is definitely not true for everyone, or probably even a majority of people.

Bells work great. Most people recognize the classic "brrrring, brrrrrring" as a bicycle bell and will just move right or not move at all, which is fine too. Too much confusion with "on your left", most people don't understand it, many think you are telling them to move to their left, which will of course put them right in your path.

Ah bells. South Carolina requires a bell or other sounding device on every bicycle. A judge on Hilton Head Island interpreted the "other sounding device" can include the riders own voice.

Bell: usually ignored. Pedestrian would turn around, stop, and look at me, causing me to strike them on two occasions.

Voice: very effective if the rider/pedestrian your overtaken understands the language you are using. I've had to learn a Spanish phrase to warn some pathway users.

Horn: the pathway parts like Moses parting the Red Sea. My theory is Americans are now conditioned to a horn being from a car. I only used a horn on my tandem and tag-along setup, as that was about 600 pounds of rolling stock on the pathway.

All that being said, causal bike riding tourist seemed to be oblivious to all manner of pathway etiquette. Riding two abreast, blocking the path with parked bikes, and not looking where they are going.

I was grouping bells and horns when I mean't I could yell louder then a bell but grouping was done because a person would need to free up a hand to work either instead of braking.

i have a bell on my pedicab and it's very useful. I ring when far off and then when closer. If people still don't move, I either wait or say "pardon me"