I had one, but needed to go to the gym because of motivtion. I just can't work out at the house.
It worked really well (if your motivated). It is very different from free weights. You have to work very slow. Take about 6 seconds to complete 1 rep. It cuts you up and burns fat very well. But if you are looking for big muscle mass go to the free weights.
Also the Bow Flex is not near as dangerous.
If you can work out at home I say go for it.