To me, a tazer just seems to be a way of taking the moral "high ground." I never subscribed to the every life is precious story so I don't feel the need to go with something with a questionable track record. If lethal force is justified, use lethal force. If it isn't, there are plenty of other things I'd chose over a tazer, including but not limited to, lights, OC spray, knives, fists, and (the most important) my brain.
And it's Killer Angel... as in the book