I agree with MusicalJess. It's a good stopgap if you don't feel "gym" or normal exercise ready, but beyond that you'll still feel wanting after using it. I think the best part about it is the information, tracking, and goals. It allows you to kind of itemize your weight loss, place certain goals, and improve your posture and balance.
As a gamer I was pretty disappointed and returned to the Xbox, but I don't you're looking at getting one for that reason.
My bottom line would be, if you feel you're "gym ready" - spend the money on a membership instead.