vision system accuracy

[ns3517]

For those of you who don't mind sharing here are a few questions i'd like to ask.
1. How accurate has your vision tracking been in a competition.
2. Have you had any on field problems preventing it from working if so what problems.
3. What kind of vision system do you use. [meaning reflective light targeting, flashlight, or camera]
4. Does your system work from the defenses.