I love the Sleeper Hero and so do my kids. I first found Sleeper Hero online when my son was 3 and transitioning to a big bed. We had trouble keeping him in his bed at night and in the morning. We tried an "Okay to Wake" clock but he would end up fiddling with it all night. I order the Sleeper Hero and started using it right away.
It comes in a very nice box with a Sleeper Hero that you get to name and a great hardcover book. The book talks about how your child doesn't have to be scared at night because he has Sleeper Hero with him. It also explains how Sleeper Hero has a light on his chest that is red for when it's time to stay in bed and then will turn green when it's okay to wake up. Our Sleeper Hero is named Bob and my son used if for almost a year. In the morning I would hear, "Sleeper Hero is green! Sleeper Hero is green!" as he ran downstairs. Now, my 1.5 year old is showing interest in Bob. He's still in his crib (and will be for a long time, hopefully!) but he enjoys watching Sleeper Hero turn green every morning.
You can buy your Sleeper Hero here: