I've been looking at this for a while now, the one BBK has looks about the best IMHO. Personally I'd want it to be fully automated, I'd forget to switch on anything manual, like a phone app or go-pro style cam. Auto loop recording, auto on at ignition, and parking mode with one of the little gizmos that protects your battery, front and rear if possible. Not sure about GPS data though, it could work against you in certain scenarios.