I had that ding dong bell from Niagara, but it was stolen by my girlfriend's brother for his bike. It is very loud, but it's also the size of a small burger. I also have that brass bell from Velo Orange. It's not quite as loud as the ding dong bell, but the sound is a very crispy "tinggg..."
small burger is good
very crisp "tingg" is good
you talked me into getting both