I'm currently using a Canadian keyboard, with the keys remapped to their "proper" US QWERTY layout. The only noticeable difference now is that the backslash key now exists to the left of Enter (Entrée), and between Shift and Z. That's right, two backslash keys. I'll have to see if I can get used to this strange layout. Otherwise, I'm only out $15 for two of them (I got them specifically so I could have the same keyboard layout at home and at work). :)
Why do Canadians need a mu key? Do Canadians type mu so much that they need a mu key? It's AltCar+M on this keyboard.