Get loaners of whatever system you are looking at and try them out for 30 days.
What works for one agency may be completely wrong for another agency.
A rural Sheriff's office or Highway Patrol needs a lower F/stop lens than does NYPD, LAPD, or an agency with lots of ambient lighting.
Dear God, this is one of the dumbest ideas I've ever heard. It's got to rank right up there with CALEA. -Pepper45
Bastard! - TBO