There is no doubt that these guys in the commercials received their bodies from training hard and more then likely NOT from a Bowflex. But understand this; you can get a solid body from one of those machines; heck and machine or fad product. The thing is you have to work hard and if you do then you will see results. The only problems with these things is you "out grow" them.
If you are going to spend any monies for a home workout then picked up weight plates, dumbbells, barbells and a good solid bench. These you can pick up more as you grow to continue your lifting; and the exercises are endless because they provide more variety. With the Bowflex you have limited amount of movements for workouts and that will kill any buzz for working out; not to mention make your body become stagnant so that results will be harder to obtain and you probably will see results reverse. But if something like this gets you started on something then that is good and when you see results for your hard work and realize you are outgrowing it; then perhaps you will then move into some real equipment or get a gym membership.