General public can't legally buy MACE here in Indiana, Only LEAs. Make sure of what your getting, mace is a pretty loose term, it can mean many things including pepper spray....but pepper spray is NOT MACE. Hope that makes sense
Pepper spray is just that, highly concentrated chemical with the active ingredient form the OC (Oleoresin Capsicum) genus of plants.
"MACE" (while loosely used for other things) is a cocktail of man made chemical.
I would assume "MACE" is much more potent and volatile since it is restricted here. I'm not in favor of key chain sprays, unless they have some kind of REALLY good cap or safety. Tossed in a purse or pocket, could be disastrous. +1 to what Jager78
said......TRAINING. Defensive sprays can be just as hazardous to the user, as it can be to an assailant. Make sure you research the law also. In the world we now live in, one or both of these could
have legal repercussions, you want to be prepared and not get blindsided.