Why don't they do more studies about amount of lives saved?

how bout pepper spray? sure it doesnt work all the time but it doesnt kill when it doesnt work. crack does not make anyone obtain super human strength...

Deaths associated with stun-gun use
Supporters say that stun guns are a safer alternative to devices such as firearms. Taser brand of stun guns were originally marketed as "non-lethal" devices. However, based on the judgements of the SEC, this has had to be amended as "less-lethal" devices.[5]

Between September 1999 and October 2004, there were 73 cases of deaths of subjects soon after having been shocked using Tasers. Of these cases:

In 8 cases, medical examiners said Tasers were a cause or a contributing factor or could not be ruled out as a cause of death.
In 18 cases coroners and other officials stated that Tasers were not a factor.
In most of the 73 cases, drugs including cocaine, methamphetamine, and PCP were concluded to be the major factor leading to death.
In many cases pre-existing cardiovascular conditions or other medical conditions were stated to be a factor.
Several deaths occurred as a result of injuries sustained in struggles. In a few of these cases head injury due to falling after being shocked contributed to later death.
These incidents form a very small percentage of many tens of thousands of operational uses of tasers.[6]

Various lawsuits against the manufacturers and users of stun guns are pending, but many court judgements have dismissed lawsuits by finding evidence of preexisting conditions, ranging from excited delirium (caused by a subject's interaction with high levels of drug-use) which may be a factor before cardiac arrest, and preexisting osteoarthritis which may make bone fracture more likely when the device is used on the subject.

Critics argue that although the medical conditions or illegal drug-taking of some of these casualties, may have been the proximate cause, the use of the taser may have significantly heightened the risk of death for those suspects in an at-risk category. Therefore, they argue, this suggests that tasers and other electroshock weapons may be too dangerous to use on people with certain medical conditions. Furthermore, since police officers will typically not know about a person's medical conditions or the contents of his/her bloodstream, this entails a risk of death with virtually any suspect.

Supporters say that stun guns and tasers are more effective than any other means including pepper-spray (an eye irritant/breathing irritant), batons (and other conventional ways of inflicting pain), hand-to-hand combat (i.e. wrestling a subject to the ground), or even hand guns, at bringing a subject down to the ground with a minimum physical exertion, and with a minimum of potential for injury. Stun-guns have a direct link to reduced injury from use of physical force, and are attributed to saving human lives by use as an alternative to the use of firearms to subdue violent or out-of-control subjects. However, critics charge that police officers who are risk-averse will also resort to tasers in situations where previously they would have used more conventional, less "extreme" techniques, such as trying to reason with a cornered suspect. from Wikipedia.org

no one here is defending criminals... but should the penalty for a guy that is too stoned to hold still be death?

I ride the downtown streets of the city everyday... about 300 kms a day... mostly downtown... I have no tools to defend myself against the very same thing the police see...