I tried one out on my bedroom TV last week. It was great. With "normal" TV using the batwing antenna I was getting about a dozen channels of varying degrees of clarity. With the converter box, I got 30 crystal-clear digital channels off the same batwing antenna.
If you know how to use your batwing antenna to get "normal" TV, then using the box is easy. Instead of the antenna cable going into the TV or into a switch, you run it into the box. Out of the box, you can use either a cable to go to where your antenna cable went or you can use the audio/video (red/white/yellow) component cable to go to one of the inputs on your TV.