I would highly recommend NOT getting this machine. For the fact that you are lying down completely taking all your stabilization muscles and letting them lay down too. And you will NOT get a 6-Pack or loss weight from just using this machine. In order to get those results you need a healthy "diet", a proper cardio program, and a proper weight lifting program.
Just think of what you are trying to train your body to do. If you're trying to teach it to be really good at trunk flexion, get the machine. But if you move around, carry things, change in direction. You need to be doing more exercises like Stability Ball Crunches, Lunge w/ Med. Ball Twist, Med. Ball Woodchops, etc..