The SmartMiles 'black box' just seemed to be very inaccurate - my breaking and acceleration scores were very poor even though I drove as if I was taking my test every journey. The speed score seemed to work fine, but having a curfew at 10:00pm is ridiculous as that isn't that late at all, and often I'd find myself having to come back from work after those hours, again giving me a very poor score. Overall, it did the job in getting my insurance cheaper for the first year but it was the cause of a lot of stress as due to the inaccuracies of its recordings, I nearly wasn't eligible for the discount. - James