I don't have the Iron Gym specifically, but I installed a chin-up bar at my house. I use chin-ups and pull-ups to compliment my workouts at the gym, but not to replace them. If I were only working upper body, and didn't want to join a gym, I would probably stick to doing weighted pull-ups, push-ups at different angles, and dips for free elsewhere, such as local playgrounds. The dips that the Iron Gym allow you to do target the triceps more than a chest/tricep dip on bars would allow, and it doesn't look like it lets you dip very low. You could probably get the same results using 2 chairs, one holding your feet, and the other using your hands to do the dip. A bench is sturdier if you have one.
My chin-up bar was about $15, and is permanently and safely installed in my wall. I should be able to tell if it's going to fall off due to a cracking sound in wood. The Iron Gym is about $30, and since it's not permanently installed on your door, I only wonder about the safety. If the price of the Iron Gym were lower when I went to buy my chin-up bar (it was about $50 or so at the time), I probably would have bought it. I like that it allows different grips that my small chin-up bar doesn't allow (such as a wide grip).