It is favored by people who want to subdue a suspect or assailant without killing him, but is opposed by some people and groups (like Amnesty International). In rare cases, being shot with a taser has resulted in death. 
YouTube has some videos of young men resisting arrest, getting tasered, and then claiming the police used excessive force or abused their authority.
- Forget Tupperware: Taser Parties Are the New Craze, Associated Press, Fox News, January 4, 2008
- UCLA student without ID refuses to leave the library at night
- Don't tase me, bro! - student resists arrest at Kerry forum
- Michell Malking blog entries show that the student had rushed toward the stage and cut in line to ask his question, his mike was cut off when he said a dirty word, etc.
- Speedin Ticket Taser - The officer orders the man to put his hands behind his back, and pulls out a taser. The man refuses, says, "What the heck is wrong with you?", and then walks away while reaching toward his pocket.