Personally, I'm torn on the autostop feature. I used it when I first got mine but then I decided that it was not representing what I was doing in training. Like on a group ride, we all stop at certain intersections to wait for everyone to regroup. We've waited for up to 5 minutes for everyong to get together. I figured if I'm resting for 5 minutes in the middle of my ride, it should be reflected in the data and not show a faster average speed than I was really doing.
Anyway, I stopped using the autostop feature and now I have to live with forgetting to stop the thing and then having so much data recorded I can't download it to my lap top.... there's no winning!