I have one from Allstate and I've just had it long enough (30 days) to start getting ratings. Mine doesn't beep (that I noticed) during braking, so I have to wait until the web site updates. It cares about how many miles you drive, the time of day (increasingly higher risk as you get later in the day), how many hard/extreme braking events you have, and if you exceed 80 mph. While I've never exceeded 80, I have driven a lot lately. I moved about 90 miles from most of my family as well as a house I rent out, and I live about 30 miles from my girlfriend. I also tend to drive home late in the evening a lot. And perhaps most surprisingly, I have a lot of hard braking, usually when there's tons of traffic on the turnpike and people continue to jam on their brakes. Now that I've seen the rating, I'm going to see if I can really decrease my hard braking. My initial discount was 10% but right now it's estimating 0% discount, so obviously, if things don't improve, I'll be sending it back!