A lot of people, including myself, confuse tasers with stun guns, so I’ll answer both.
The best taser will fire its leads at high speed, and have long barbs. Most taser failures happen because the leads get entangled in the target’s clothing, and these features help minimize that. That being said, taser failures will still occur.
The stun gun’s biggest weakness is that the user has to be very close in order to use it. The best stun gun will have a long reach
As David says, people conflate “Taser” (a specific product from Taser International” and “stun gun”, a generic item produced by dozens of manufacturers in various degrees of quality.
There is only one Taser model available to civilians, the Taser Pulse which is 400.00. It’s not legal everywhere.
Tasers are a one-shot item and there are many failures. We police use them only when we have backup available.
best tasers 2018 are, in the opinion of most, essentially useless. They are a “pain-compliance” device. They hurt while they are in contact with the person. They do NOT induce unconsciousness or knock people to the ground. If the person is drunk or on drugs, it may just make them mad.
I found an interesting article on this subject, I leave it here, it may help someone! Good luck!