Here's how I look at it: There are situations where a partition would save a life, in which a camera would not. There are situations in which a camera would save a life, in which a partition would not.
In my opinion, the partition is a better protector to the imminent threat but the camera is a better deterrent to the potential threat.
I think what it comes down to from a driver's perspective is the comfort factor. Some drivers feel very uncomfortable physically in a cab that has a shield while some drivers would feel very uncomfortable psychologically in a cab without one.
Regarding the camera, the thought that somebody is always watching would be comforting to some drivers while others would view this as an invasion of privacy.
For the owners it usually comes down to cost. Having a partition is generally less expensive than a camera but the camera may afford the owner more options for the vehicle, which could make the cameras financially viable.
