These are worth every penny. I've went down a few times now and every time I go down on throttle side I know that my brake will rotate as it should, and it does.
Pick the bike back up and go! No broken levers, or master cylinders!
Make sure you don't tighten it too much, otherwise it won't rotate; but make sure it's not too loose either, otherwise you'll be riding and it'll come loose :(