I have a few friends with the box, one doesn't measure his speed it's just for millage. and the other constantly monitors his speed.

I suppose it's all just pre arranged but i'd be pissed if i took the insurance out they fitted it and you found they knew exactly how fast you were going at a certain time.

I can't see it having any recording of data of your braking and accelerating forces because what about evasive maneuvers and the like?