I occasionaly use Aquamacs on my Macbook Pro. I have also bought an Apple keyboard with a US english layout, because it is not practical to program on a Mac with a french (or more generally probably any non english) layout. These characters { } | \ ~ [ ] are not even on the keyboard, and you have to use various combinations of meta keys to get them.
Of course it doesn't work well when you need: M-\ , because typing backslash already requires meta keys.
So, how do you use Emacs on a non english keyboard, if that is even possible ?
I could switch the built-in keyboard layout to english, but that's not really comfortable to use it for a long time. I do it when I have no other choices, for example when at some point I need a lot of braces, but that's just temporary.