I bought this for the wife. She loves the US Bigget Loser show and wanted to do something to keep fit, which would fit in with her busy work/mother lifestyle. This fits in just fine. She started with a light routine that was geared for those returning to exercise after some time off. Even that was hard work, so get prepared to sweat. Yes, it really makes you work hard.
I guess, like many of these things, it depends very much on your self motivation. You wont lose weight just looking at the packaging. You have to get off your backside and switch it on. And be switching it on regularly to make it of any use.
It's good, and at less than the price of a months Gym membership, it's definitely worth a try if you are in two minds.